Health

Maintenance Dose Calculator (Pharmacokinetics)

Calculate the maintenance dose MD = (Cl × Css × τ)/F to keep drug concentration at steady state. Adjust for bioavailability, clearance, and dosing interval.

Anion Gap Calculator

Calculate the anion gap from sodium, chloride and bicarbonate, correct it for low albumin, and read it against your lab range with a delta ratio.

Alveolar Gas Equation Calculator

Calculate alveolar oxygen pressure (PAO₂) from FiO₂, atmospheric pressure, PaCO₂, and respiratory quotient. Includes A-a gradient interpretation.

Loading Dose Calculator

Calculate a drug loading dose with LD = (Vd × C_target) / F, for IV or oral bioavailability, against current digoxin, phenytoin and vancomycin practice.

Grams to Calories Calculator

Convert grams of protein, carbs, fat, and alcohol to calories using the Atwater factors (4, 4, 9, 7 per gram), with each macro's share of the total.

Volume of Distribution Calculator (Vd)

Calculate pharmacokinetic Volume of Distribution Vd = Dose/C₀. Classifies distribution as plasma-bound, extracellular, or tissue-bound with reference drugs.

Burn Area Calculator (Rule of Nines)

Estimate total body surface area burned with the Rule of Nines, plus the American Burn Association referral tier and Parkland fluid volumes.

Chemotherapy BSA Dose Calculator

Convert a body-surface-area-based dose (mg/m²) into a total milligram dose. Computes BSA using Mosteller, DuBois, or Haycock formulas from height and weight.

Contraction Frequency Timer

One tap per contraction. See how many fell in the last 10, 30 and 60 minutes, the rate per hour, and whether the pattern meets the timing half of 5-1-1.

Contraction Timer

Tap when each contraction starts and again when it ends. Shows how long each lasts, how far apart they are, and checks all three parts of the 5-1-1 rule.

Coronary Heart Disease Risk Calculator

Estimate 10-year coronary heart disease risk using the Framingham ATP III point score. Inputs: age, sex, cholesterol, blood pressure, smoking, diabetes.

Dead Space Calculator

Calculate pulmonary dead space using the Bohr equation. Enter arterial CO2, mixed expired CO2, and tidal volume to find the dead space fraction and volume.

Ejection Fraction Calculator

Calculate ejection fraction from end-diastolic and end-systolic volumes, graded on the 2015 echo ranges for men and women, with stroke volume and output.

First-Trimester Risk Calculator (Maternal Age + NT)

Estimate first-trimester risk from maternal age and nuchal translucency measurement. Combines age-based background risk with NT-derived likelihood ratio.

Glasgow Coma Scale Calculator

Score the Glasgow Coma Scale from eye, verbal and motor responses, with untestable parts, the GCS-Pupils score and the severity band from mild to severe.

Menstrual Cycle Phase Calculator

Find which menstrual cycle phase you are in today from your cycle length and days since your period began, with ovulation day and the fertile window.

Modified Fisher Scale Calculator

Grade subarachnoid hemorrhage on the Modified Fisher Scale. Enter CT findings to get the grade and estimated vasospasm risk after aneurysmal SAH.

MRSA Risk Score Calculator

Estimate MRSA colonization or infection risk using common community and healthcare-exposure factors. Adds known risk markers into a simple total score.

Neonatal Assessment Calculator

Calculate three neonatal metrics: APGAR score from five clinical signs, gestational age from last menstrual period, and birth weight percentile for age.

Neonatal Bilirubin Calculator

Check a newborn bilirubin against the AAP 2004 phototherapy lines by age in hours and risk group, in mg/dL or µmol/L, with the rate of rise. 35 weeks and up.

OHSS Risk Calculator (Ovarian Hyperstimulation)

Check IVF stimulation against the published OHSS risk markers: age under 33, AMH, antral follicles, PCOS, and the day-of-trigger follicle count and estradiol.

Palliative Performance Scale (PPS) Calculator

Derive a Palliative Performance Scale score from five clinical domains using the leftward-precedence rule. Level criteria and survival ranges included.

Pediatric Weight-Based Dose Calculator

Convert a weight-based prescription (mg/kg) into a per-dose and daily total in milligrams. Includes maximum dose capping and total course quantity.

Sepsis Calculator (qSOFA Score)

Screen for sepsis with the qSOFA score. Enter respiratory rate, systolic blood pressure, and mental status to flag patients at risk of organ dysfunction.

Stroke Risk Calculator (ABCD2 Score)

Calculate stroke risk after a TIA using the ABCD2 score. Enter age, blood pressure, clinical features, duration, and diabetes for 2-day and 7-day risk.

Surgery Risk Calculator (Revised Cardiac Risk Index)

Estimate cardiac risk before non-cardiac surgery using the Revised Cardiac Risk Index. Six clinical predictors give a risk class for major adverse events.

WHO Weight-for-Age Z-Score Calculator

A child's weight-for-age z-score and percentile from birth to 5 years on the official WHO LMS tables, with the WHO underweight cut-offs, in kg or lb.

Chicken Breast Calorie Calculator

Calories and protein in a chicken breast by weight, comparing grilled, poached, pan-seared, fried and rotisserie side by side, with raw-to-cooked weights.

Circadian Rhythm Calculator: Your Body Clock Timeline

Map your body clock from your usual bedtime and wake time: melatonin onset, the body-temperature low, when light shifts you earlier, and a caffeine cut-off.

Cold Plunge Duration Calculator

Find a sensible cold plunge time for your water temperature in °C or °F and your experience, with a weekly plan, a ceiling not to pass, and when to skip it.

Harris-Benedict BMR Calculator

Calculate basal metabolic rate using the Harris-Benedict equation. Enter sex, age, weight, and height to estimate daily calorie needs at rest and with activity.

HRV Score Interpretation Guide

Interpret your HRV score against your 7-day baseline or the typical RMSSD range for your age. Shows recovery status and a training readiness call.

Karvonen Heart Rate Calculator

Calculate target heart rate training zones using the Karvonen formula. Enter age and resting heart rate to find your personalized intensity zones for exercise.

Metabolic Equivalent (MET) Calculator

Calculate calories burned by any physical activity using MET values. Enter your weight, choose an activity, and set the duration to estimate energy expenditure.

Nurse-to-Patient Ratio Calculator

Calculate nurse-to-patient ratios and compare to safe staffing guidelines. Enter total patients and nurses on shift to see the ratio by hospital unit type.

Nutrition Label Calculator

Build a nutrition label from macronutrient grams. Enter protein, carbs, fat, fiber, sugars and sodium for total calories and FDA percent daily values.

Optimal Sleep Temperature Calculator

Find your bedroom temperature from age, build and preference: the 15.5-19.4C general advice, the warmer band older adults sleep best in, and why REM goes first.

Plasma Osmolality Calculator

Calculate plasma osmolality from sodium, glucose, and BUN levels using the standard clinical formula. Assess fluid balance and detect electrolyte abnormalities.

Post-Workout Protein Timing Calculator

Calculate optimal post-workout protein per meal and daily total from body weight. Covers timing window, protein per session, and hypertrophy targets.

Protein in Chicken Calculator

Protein in chicken breast from raw or cooked weight across 11 cooking methods, with the raw-to-cooked conversion and your share of a daily protein target.

Red Light Therapy Dose Calculator

Calculate red light therapy dose in joules per cm2 from irradiance and session time. Includes therapeutic dose ranges for surface and deep tissue treatment.

Sauna Session Planner

Plan sauna session length by temperature for dry Finnish, steam, and infrared saunas. Includes heart rate guidance and beginner versus advanced time limits.

Shrimp Calorie Calculator

Shrimp calorie and macro calculator by preparation method and serving size. Covers boiled, grilled, scampi, fried, tempura, cocktail, and coconut shrimp.

Smoking Risk Calculator

Calculate pack-years from cigarettes per day and years smoked, see how far your risk has fallen since quitting, and check the USPSTF screening criteria.

Sun Safety Calculator

Calculate how long you can stay in the sun before burning. Enter UV index, skin type, and SPF to get your estimated safe sun exposure time in minutes.

Urine Specific Gravity Calculator

Interpret urine specific gravity to assess hydration and kidney function. Enter your USG reading to see what it means and how to adjust your fluid intake.

Alcohol Habit Annual Cost Calculator

Calculate yearly alcohol spending from drinks per week, average price per drink, and bar vs home consumption. See 5 and 10 year totals.

Body Adiposity Index (BAI) Calculator

Estimate body fat percent from hip circumference and height using the BAI formula. A BMI alternative needing only a tape measure, with age and sex bands.

Sunscreen Coverage Calculator

Calculate how much sunscreen you need for full body coverage. Most people apply too little. Find the right dose for real SPF protection.

UV Safe Sun Exposure Time Calculator

Calculate safe sun exposure minutes before burning from skin type and UV index. Includes sunscreen adjustment and vitamin D synthesis time estimates.

Body Fat Goal Calorie Calculator

Calculate the daily calorie deficit and timeline needed to reach your target body fat percentage while preserving muscle mass.

Bone Density T-Score Interpretation

Interpret a DEXA scan T-score against the WHO thresholds for normal, osteopenia and osteoporosis, with Z-score guidance and what drives fracture risk.

Chronotype Sleep Preference Calculator

Find your chronotype, from morning lark to night owl, with your free-day mid-sleep, social jetlag in hours, and when melatonin should start rising.

EPOC After-Burn Calorie Calculator

Estimate calories burned after exercise through EPOC (Excess Post-Exercise Oxygen Consumption), the afterburn effect from high-intensity workouts.

Exercise Hydration Calculator

Calculate how much water to drink before, during, and after exercise based on your body weight, sweat rate, and workout intensity.

GAD-7 Anxiety Score Calculator

Score the GAD-7 anxiety questionnaire. Returns a total from 0-21 with minimal, mild, moderate, or severe ratings and recommended next steps for each level.

Gallstone Risk Calculator

Score your gallstone risk from age, sex, BMI, family history, rapid weight loss, diabetes and estrogen, and see which factors you can actually change.

Herd Immunity Threshold Calculator

Calculate the vaccination coverage needed to achieve herd immunity based on a disease's basic reproduction number (R₀) and vaccine efficacy.

Home Gym vs Gym Membership Break-Even Calculator

Calculate when your home gym equipment investment pays for itself compared to a monthly gym membership. Includes maintenance costs and joining fees.

Kidney Stone Risk Calculator

Check your fluid intake against the 2.5 litre urine target, and which kidney stone risk factors apply to you: salt, protein, BMI, a past stone, family and heat.

PHQ-9 Depression Screening Score

Calculate your PHQ-9 (Patient Health Questionnaire) score to screen for depression severity. Rate 9 symptoms over the past 2 weeks.

Protein Source Cost Comparison Calculator

Compare cost per gram of protein from eggs, chicken, beef, tofu, and other sources. Find the most budget-friendly high-protein foods ranked by cost efficiency.

Sleep Deprivation Productivity Cost Calculator

Estimate the economic cost of sleep deprivation based on reduced productivity, increased errors, and health impacts at work.

Sunscreen SPF Protection Time Calculator

Calculate sunscreen time from SPF, Fitzpatrick skin type (I-VI), and UV index. Returns exposure window and reapplication schedule for outdoor activities.

VO2 Max Estimation from Step Test

Estimate VO2 max from the Queens College 3-minute step test and your 15-second recovery pulse, rated on Cooper Institute norms by age and sex.

Wells PE Score Calculator

Calculate the Wells clinical prediction score for pulmonary embolism (PE) pretest probability. Helps clinicians determine if further testing is needed.

Blood Glucose Unit Converter

Convert blood glucose between mg/dL (USA) and mmol/L (international) instantly. Includes fasting, pre-diabetes, and diabetes reference ranges in both units.

Ovulation Calculator

Predict your ovulation date and fertile window based on your last period and cycle length. Find your 6-day fertility window and peak conception day.

Absolute Risk Reduction (ARR) and NNT Calculator

Calculate ARR, RRR, NNT and relative risk from control and treatment event rates, with 95% intervals when you add group sizes and the time frame the NNT covers.

Apgar Score Calculator

Score the Apgar at 1, 5 or 10 minutes after birth: appearance, pulse, grimace, activity and respiration, read by timepoint as AAP and ACOG advise.

Blood Alcohol Content (BAC) Calculator

Calculate your blood alcohol content (BAC) using the Widmark formula. Know your impairment level, legal status, and time until sober before driving.

Dietary Reference Intake (RDA/RDI) Calculator

Look up the RDA, Adequate Intake and upper limit for nine vitamins and minerals by age, sex, pregnancy and breastfeeding, from the National Academies tables.

Glycemic Load Calculator

Calculate the glycemic load (GL) of a serving from its glycemic index and carbohydrate, for US or EU labels, with GI values from the 2008 International Tables.

HbA1c to Blood Glucose Converter

Convert HbA1c percentage to average blood glucose (mg/dL or mmol/L) and back. Includes diabetes classification using ADA 2008 formula.

Head Circumference Percentile Calculator

A child's head circumference percentile and z-score by age and sex, birth to 5 years, on the official WHO tables. Flags readings past 2 SD either way.

Insulin-to-Carb Ratio and Correction Factor Calculator

Calculate insulin-to-carb ratio (ICR), correction factor, and mealtime insulin dose. Estimates blood sugar correction for Type 1 and Type 2 diabetes management.

Medication Half-Life and Clearance Calculator

Calculate drug concentration over time using half-life. Find time to steady state, time to clearance, and peak and trough levels for pharmacokinetics.

Number Needed to Treat (NNT) Calculator

Calculate NNT, NNH, ARR, RRR, relative risk, and odds ratio from clinical trial event rates. Essential tool for evidence-based medicine.

Pulse Pressure Calculator

Calculate pulse pressure and mean arterial pressure (MAP) from blood pressure readings. Understand what narrow or wide pulse pressure means for your health.

Relative Risk and Odds Ratio Calculator

Relative risk, odds ratio, risk difference and NNT from a 2×2 table of counts, each with a 95% confidence interval and a zero-cell correction.

Sobriety Calculator

Calculate how long you have been sober. Track your clean days, weeks, months and years, and see your next sobriety milestone.

CHA₂DS₂-VASc Stroke Risk Calculator

Calculate the CHA₂DS₂-VASc score for atrial fibrillation patients. Estimate annual stroke risk and determine anticoagulation therapy recommendations.

Child Growth Percentile Calculator

Height, weight and BMI-for-age percentiles for ages 2 to 20 on the official CDC LMS tables, in inches and pounds or cm and kg, with the 2022 obesity classes.

Cigarette Cost Calculator: Lifetime Smoking Cost

Calculate how much smoking costs over your lifetime in money, time, and health. Enter your daily cigarettes and pack price to see the shocking total.

Cold Water Survival Time Calculator

Estimate time to exhaustion and survival time in cold water, in °F or °C, from the boating-course table, plus the 1-10-1 rule and what to do if you fall in.

Conception Date Calculator

Estimate when conception occurred by working back from due date or birth date. Returns conception date range, first trimester start, and ultrasound comparison.

Drug Half-Life in Body Calculator

Calculate how long a drug stays in your body from its elimination half-life. See percentage remaining, time to full clearance, and concentration over time.

eGFR and CKD Risk Calculator (KDIGO Grid)

Estimate eGFR with CKD-EPI 2021, then add a urine albumin-to-creatinine ratio to place it on the KDIGO risk grid, with the testing and referral it implies.

Eye Prescription Calculator & Converter

Read your eyeglass prescription: sphere, cylinder, axis, and spherical equivalent. Converts between plus-cylinder and minus-cylinder notation.

Steps to Miles & Km Calculator

Convert steps into miles, kilometers, and calories using your own step length rather than the 2,000-steps-per-mile rule that fits almost nobody.

Wells Score DVT Calculator

Calculate the Wells score for deep vein thrombosis (DVT) risk. Determine pretest probability to guide D-dimer testing and imaging decisions.

Meal Calorie Counter

Estimate calories in your meal by adding up common food items. Covers portions of bread, rice, meat, vegetables, dairy, and drinks.

BMR Calculator (Basal Metabolic Rate)

Calculate your Basal Metabolic Rate using the Harris-Benedict or Mifflin-St Jeor equation. Find your daily calorie burn at rest.

Compression Stocking Size Calculator

Find your compression stocking size from ankle and calf circumference in cm or inches, with US mmHg levels and the European and UK class numbers.

VO2 Max Training Zones Calculator

Get the five training zones by percent of VO2 reserve using heart rate reserve, not just percent of max heart rate. Karvonen and Tanaka, side by side.

Acetaminophen (Tylenol) Dosage Calculator

Calculate the correct acetaminophen (Tylenol, paracetamol) dose for adults and children based on weight and age. Avoid dangerous overdose with accurate dosing.

BUN-to-Creatinine Ratio Calculator

Calculate the BUN to Creatinine ratio to assess kidney function and help differentiate pre-renal, renal, and post-renal causes of elevated BUN or creatinine.

Calories Burned Running Calculator

Calculate calories burned running or jogging based on distance, speed, weight, and terrain. Find the metabolic equivalent (MET) and compare to walking.

Daily Carbohydrate Target Calculator

Calculate your recommended daily carbohydrate intake based on your calorie needs, activity level, and goals. Get targets for total carbs, fiber, and net carbs.

Daily Fat Intake Calculator

Calculate your recommended daily fat intake based on your calorie needs and health goals. Find target grams of total fat, saturated fat, and unsaturated fat.

Framingham 10-Year Heart Disease Risk Calculator

Estimate your 10-year cardiovascular disease risk with the 2008 Framingham general CVD equations: age, cholesterol, blood pressure, smoking, diabetes.

HEART Score for Chest Pain Calculator

Calculate the HEART Score for chest pain in emergency settings. Stratify risk of major adverse cardiac events (MACE) to guide clinical decision-making.

HOMA-IR Insulin Resistance Calculator

Calculate your HOMA-IR score to estimate insulin resistance using fasting blood glucose and fasting insulin levels. Assess your metabolic health risk.

Ibuprofen Dosage Calculator

Calculate the correct ibuprofen dose based on weight and age. Find safe dosing intervals for adults and children for pain relief and fever reduction.

LDL Cholesterol Calculator (Friedewald Equation)

Calculate your LDL (bad) cholesterol using the Friedewald equation from a standard lipid panel. Understand your cardiovascular risk from cholesterol numbers.

Smoking Recovery Benefits Timeline

See the health benefits of quitting smoking on a timeline, from 20 minutes after your last cigarette to 15 years later. Calculate your personal milestones.

Waist-to-Height Ratio Calculator

Calculate waist-to-height ratio (WHtR), a measure of central obesity that predicts cardiovascular risk better than BMI alone for all ages and ethnicities.

Allergy Severity Score Calculator

Score nasal, eye, skin and chest allergy symptoms out of 15, see the ARIA mild or moderate-severe grade, and spot the combinations that need urgent care.

Ankle Sprain Recovery Calculator

Estimate ankle sprain recovery time from Grade 1, 2, or 3 severity, age, and activity level. Get a week-by-week rehab timeline and return-to-sport milestones.

Ankle-Brachial Index Calculator

Calculate your Ankle-Brachial Index (ABI) to screen for peripheral artery disease. Enter ankle and arm blood pressures to get your ABI score.

Antibiotic Course Completion Calculator

Calculate days remaining in your antibiotic course and track doses to ensure full prescription completion. Returns daily dose schedule and warning if missed.

Basal Body Temperature Tracker

Check a basal body temperature (BBT) reading against your six-day high with the Sensiplan rule to confirm ovulation. Works in Celsius or Fahrenheit.

Birth Control Reminder Calculator

Calculate how many pills remain in your pack, days until next pack, and set a refill reminder timeline. Never run out of birth control again.

Blood Donation Recovery Calculator

How long plasma, hemoglobin and iron stores take to come back after giving whole blood, platelets, plasma or double red cells, with your next eligible date.

Blood Pressure Average Calculator (Up to Three Readings)

Average two or three blood pressure readings and get the category of the average, with each reading staged and home readings judged on home values.

Blood Pressure Risk Level Calculator

Score your cardiovascular risk factors together: blood pressure, age, cholesterol, smoking, diabetes, family history and BMI, using AHA categories.

Blood Volume Estimator

Estimate total blood volume in liters from height, weight, and sex using the Nadler equation. Useful for surgical planning and transfusion medicine.

Body Symmetry Measurement Calculator

Measure left-right body symmetry by comparing limb and body measurements. Useful for fitness, rehabilitation, and injury monitoring.

Breathing Exercise Timer Calculator

Set up timed breathing exercises including box breathing, 4-7-8, and diaphragmatic patterns. Calculate total session duration.

Cholesterol Goal Calculator

Find your target LDL cholesterol from your cardiovascular risk, using the 2026 ACC/AHA goals and the ESC/EAS 2019 targets. Works in mg/dL or mmol/L.

Contact Lens vs Glasses Cost Calculator

Compare the yearly cost of contact lenses and glasses from your own prices, with lenses counted per eye and the cost of keeping a backup pair of glasses.

Cortisol Stress Load Assessment

Score the sleep, stress, caffeine, exercise and late-screen habits that push cortisol up, and check the warning signs that need a real cortisol test.

Creatine Loading Phase Calculator

Calculate creatine loading dose (0.3 g/kg/day for 5 days) and maintenance dose (3-5 g) from body weight for strength and muscle performance.

Daily Steps Goal Calculator

Calculate a personalized daily step goal from age, fitness level, and health objectives. Targets weight loss, cardiovascular health, or general activity.

Daily Sugar Limit Calculator

Calculate your daily added sugar limit from age, sex, and health goals. See your allowance in grams and teaspoons with common food and drink comparisons.

Daily Water Weight Fluctuation Calculator

Calculate natural daily weight fluctuation from body weight and activity. Returns range in lbs and kg from sodium, glycogen, and hormonal cycles.

Dehydration Risk Assessment

Assess dehydration risk from body weight, temperature, activity level, and fluid intake. Returns a rating from low to severe plus a rehydration target.

Dental Floss Usage Calculator

Work out how long a dental floss roll lasts from its length, your session length, and how often you floss. Shows the run-out date and yearly cost.

Ear Infection Risk Calculator (Children)

Score a child ear infection risk from age, daycare, feeding, smoke exposure, pacifier use, and season. Includes the symptoms that mean see a doctor now.

Electrolyte Balance Calculator

Estimate daily sodium, potassium, magnesium and calcium needs from sex, age, body weight, activity and sweat rate, using the US intake figures.

Exercise Blood Oxygen Calculator

Assess whether your SpO2 blood oxygen levels are safe during exercise. See how altitude, exertion, and fitness level affect oxygen saturation readings.

Eye Drop Supply Duration Calculator

Calculate how many days your eye drop bottle will last based on drops per day, eyes treated, and bottle size. Never run out unexpectedly.

Fever Temperature Calculator

Classify a body temperature in °C or °F from hypothermia through high fever, with age-based guidance for babies, children, adults and over-65s.

Flu Recovery Timeline Calculator

Estimate when flu should ease from the day it started, age, health and antivirals, see when the CDC says you can go back to work, and when to see a doctor.

Foot Arch Type Assessment

Find your foot arch type (flat, normal or high) from the wet test, with shoe and insole suggestions, what your pain points to, and what the trials found.

Gut Health Score Calculator

Score the habits linked to gut health, from fiber and fermented food to sleep, see your weakest area, and check the symptoms that need a doctor first.

Hand Washing Duration Calculator

Calculate the optimal hand washing duration for different situations. Learn how long each step should take for effective germ removal.

Hangover Duration Calculator

When a hangover usually ends: Widmark blood alcohol from drinks, hours, weight and sex, time to clear at 0.015% an hour, and the 18-hour survey average.

Intermittent Fasting Window Calculator

Calculate your eating and fasting windows for 16:8, 18:6, 20:4, OMAD, 14:10, and 12:12. Shows fast start and end times, and how much you sleep through.

Joint Flexibility Score Calculator

Score joint hypermobility on the 9-point Beighton scale with the 2017 age cutoffs, plus the five-part questionnaire that counts when you are one point short.

LASIK vs Glasses Long-Term Cost Calculator

Compare the lifetime cost of LASIK eye surgery against years of buying glasses and contact lenses. Find your break-even point.

Medication Expiry Safety Guide

Understand what happens to medications after their expiration date. Learn which drugs are safe to use past expiry and which ones you must replace.

Migraine Trigger Tracker Score

Rate eight common migraine triggers for a 0-100 load, then check painkiller days against the medication-overuse line and when to ask about prevention.

Mold Growth Risk Calculator

Assess the mold risk in any room based on indoor humidity and temperature. Know when conditions are dangerous and how to prevent mold growth.

Muscle Recovery Time Calculator

Muscle recovery time by muscle group, intensity, training level, age and sleep, set against the ACSM 48-hour rule, with the day and hour you are ready.

Optimal Nap Duration Calculator

Find the optimal nap length for your goal and available time. Covers 10-min power naps, 20-min stage-2 naps, and 90-min full sleep cycle naps.

Posture Ergonomics Score Calculator

Score your desk setup on six factors, from monitor height to wrist angle, see which fix gains the most, and get the OSHA and AOA screen guidance.

Pregnancy BMI Calculator

Calculate pre-pregnancy BMI and get the IOM-recommended gestational weight gain range for underweight, normal, overweight, and obese starting BMI categories.

Probiotics Dosage Calculator: Which Strain and Dose for Your Goal

Pick a goal and an age group to see which probiotic strains have trial evidence, how strong it is, and why the dose is the studied product's, not a CFU rule.

Radon Level Risk Calculator

Assess your radon exposure risk based on measured radon levels. Understand EPA action levels and when to mitigate radon in your home.

Recovery Heart Rate Calculator

Heart rate recovery (HRR) after exercise: the 1-minute drop against Cole's 12 bpm line, the 2-minute drop against 22, and effort as a share of maximum.

Resting Metabolic Rate Calculator

Calculate resting metabolic rate using Mifflin-St Jeor equation from weight, height, age, and sex. Returns calories at rest and TDEE for five activity levels.

Safe Lifting Weight Calculator

Run the full NIOSH lifting equation. Enter reach, height, travel, twist, grip, and frequency to get the recommended weight limit and lifting index.

Scar Healing Time Calculator

Estimate scar fading time from wound type, body location, age and skin tone, with the healing phases on a timeline and what silicone and sunscreen do.

Screen Eye Strain Calculator

Calculate digital eye strain risk from daily screen hours, viewing distance, break frequency, and lighting. Returns a risk score with tips to reduce symptoms.

Skin Cancer Risk Assessment (UV Exposure)

Score your skin cancer risk from skin type, blistering sunburns, family history, sun exposure, tanning beds and sunscreen, split into history and habits.

Snoring Risk Score Calculator

Score your snoring risk from weight, age, alcohol, congestion, sleep position and what a partner hears, plus the STOP-BANG sleep apnea screen alongside.

Sodium-Potassium Ratio Calculator

Calculate your sodium-to-potassium ratio and see if your electrolyte balance is optimal for heart health and blood pressure.

SPF Sun Safe Exposure Time Calculator

Calculate how long you can safely stay in the sun based on your skin type, SPF sunscreen, and UV index. Prevent sunburn and skin damage.

Standing vs Sitting Calories Calculator

Compare calories burned standing vs sitting per hour. Enter your weight and hours to see the difference and daily calorie impact.

Sunburn Recovery Time Calculator

Estimate sunburn healing time by severity grade, with a stage-by-stage timeline, the signs that need a doctor, and what changes for babies and darker skin.

Tattoo Healing Timeline Calculator

See the complete tattoo healing timeline based on tattoo size and placement. Know what to expect at each stage and when your tattoo is fully healed.

Thyroid Level (TSH) Assessment

Read a TSH (thyroid-stimulating hormone) result against the range for adults, over-70s, children or each pregnancy trimester, per the 2017 ATA guideline.

Tooth Brushing Timer and Coverage Calculator

Split your brushing time across the four quadrants and check it against the ADA's two minutes. Shows seconds per quadrant, per tooth, and the yearly shortfall.

Vaccine Schedule Age Calculator

See the vaccines the US schedule lists at each age, from newborn to 75 and over, plus pregnancy. Notes where the 2026 CDC and AAP schedules part ways.

Vitamin A Daily Intake Calculator

Calculate your recommended daily Vitamin A intake based on age, sex, and life stage. Check if you meet the RDA and avoid toxicity.

VO2 Max Estimate Calculator

Estimate VO2 max from resting and maximum heart rate with the Uth ratio, 15.3 x max / resting, rated on Cooper Institute norms by age and sex.

Wound Healing Time Estimator

Estimate healing time for cuts, grazes, burns and surgical incisions from size, site, age and health, with a phase timeline, stitch removal and tetanus advice.

Altitude Hydration Calculator

Calculate how much extra water you need at high altitude from elevation and activity, with the salt and overdrinking limits that matter up there.

Army Body Fat Calculator

Check the Army's 2026 standard, a waist-to-height ratio under 0.55, and estimate body fat with the neck-and-waist tape formula it replaced.

Blood Donation Eligibility Calculator

Check blood donation eligibility from age, weight, health and the time since your last gift, on the US rules: 17 years, 110 lb, 56 days, 3 months.

Blood Oxygen Drop Calculator (Today vs Your Usual SpO2)

Compare today's pulse oximeter reading with your usual SpO2, or with a COPD target of 88-92%, and see whether a drop is bigger than the device's error.

Blood Oxygen Level Guide

Look up what a pulse oximeter SpO2 reading means at sea level or up to 10,000 ft, from normal (95-100%) through below normal and low to critical.

Body Type Calculator

Estimate your somatotype (ectomorph, mesomorph, endomorph) from height, weight and wrist size, using the Heath-Carter ectomorphy rating and frame size.

Body Water Percentage Calculator

Estimate total body water percentage from age, weight, height, and gender using the Watson formula. Compare to healthy ranges for men, women, and older adults.

Bone Age Estimation Calculator

Compare a child's height to the average for their age and sex, see what that suggests about skeletal maturity, and learn what a real bone age X-ray adds.

Caffeine Intake Calculator

Track daily caffeine intake from coffee, tea, energy drinks, and soda. Returns total mg and shows if you are within the FDA safe limit of 400 mg per day.

Caffeine Metabolism Calculator: How Much Is Left at Bedtime

Add up to three drinks at the times you had them and see how much caffeine is left at bedtime, your peak level, and the latest time another coffee still fits.

Creatine Dosage Calculator: Daily Dose and How Long a Tub Lasts

Work out your daily creatine dose from body weight, in grams and scoops, and how many days a 300 g, 500 g or 1 kg tub lasts with or without a loading week.

Cutting Calculator

Calculate your daily calorie deficit for a bodybuilding cut. Get calorie, protein, and macro targets to preserve muscle while losing fat.

Daily Calcium Needs Calculator

Calculate recommended daily calcium intake in mg from age, gender, and life stage. Includes top dietary sources, absorption tips, and pregnancy guidance.

Daily Noise Dose Calculator

Work out what percentage of your safe daily noise limit an exposure uses up, using the NIOSH 3 dB rule. Enter the sound level and how many hours you get it.

Daily Omega-3 Needs Calculator

Calculate daily EPA and DHA omega-3 needs from age, sex, and health goals. Returns intake targets for heart health, brain function, and food source comparisons.

Daily Potassium Needs Calculator

Calculate daily potassium target in mg from age, sex, and health status. Returns adequate intake, top food sources per serving, and cautions for kidney disease.

Daily Protein Intake Calculator

Calculate your recommended daily protein intake based on weight, age, and activity level. Covers sedentary to athletic needs.

Daily Sugar Intake Calculator

Calculate daily added sugar limit per WHO and AHA guidelines from age, sex, and calorie intake. AHA recommends 25g per day for women and 36g for men.

Fetal Weight Estimator

Average fetal weight and length by week, 8 to 42, on the Hadlock 1991 ultrasound standard from week 20. Enter a scan estimate to see its percentile band.

Fitzpatrick Skin Type Calculator

Determine your Fitzpatrick skin type (I-VI) from tanning and burning response. Returns classification, melanin level, suggested SPF and burn time at UV 10.

Flexibility Score Calculator

Rate a sit-and-reach result against age and sex norms, from below average to excellent, with how far it is to the next band and how to retest it.

Folate Intake Calculator

Calculate recommended daily folate (vitamin B9) from age, gender, and pregnancy status. Returns DFE target and sources. Pregnant women need 600 mcg DFE daily.

Gestational Age Calculator

Calculate gestational age in weeks from last menstrual period. Returns trimester, estimated due date, fetal milestones by week, and prenatal appointment dates.

Grip Strength Calculator

Compare grip strength in kg or lbs with British age and sex norms. Returns a percentile, a rating and the EWGSOP2 sarcopenia cut-off for your sex.

Hearing Frequency Range Calculator

Estimate your hearing frequency range in Hz from age and noise exposure history. Compare your upper limit to the 20 Hz to 20,000 Hz normal hearing range.

Heart Rate Zones Calculator

Calculate your five training heart rate zones based on age or max heart rate. Optimize cardio, fat burn, and endurance training.

Iron Deficiency Risk Calculator

Score your iron deficiency risk from diet, periods, pregnancy, blood donation and gut health, and see the iron allowance for your age and life stage.

Keto Macro Calculator

Calculate your ideal ketogenic diet macros. Get personalized daily targets for fat, protein, carbs, and calories based on your body and goals.

Lean Bulk Calculator

Calculate daily calorie and protein targets for a lean bulk phase. Set the right caloric surplus to maximize muscle growth while keeping fat gain minimal.

Life Expectancy Calculator

Estimate your life expectancy based on lifestyle factors. See how exercise, diet, smoking, and other habits affect your expected lifespan.

Lung Capacity Estimator

Estimate predicted lung capacity (FVC) from age, height and sex with the ECCS/ERS 1993 equations, then read a spirometry result by % predicted and z-score.

Magnesium Intake Calculator

Calculate recommended daily magnesium intake by age and sex. Returns the NIH daily target in mg for children, teens, men, women, pregnancy and lactation.

Melatonin Dosage Calculator

Find a melatonin starting dose and the ceiling for your age, for jet lag, trouble falling asleep or shift work, with when to take it and why more is not better.

Muscle Mass Estimator

Estimate skeletal muscle mass from weight, height, age and sex with the Lee equation, and compare it with the MRI averages for adult men and women.

Omega-3 Intake Calculator: Add Up Your Week of Fish

Add up the EPA and DHA in a week of salmon, sardines, tuna and other fish plus supplements, and see your daily average against your omega-3 target.

Posture Score Calculator

Score your daily posture habits out of 100: sitting hours, screen height, exercise, sleeping position and breaks, with the weakest areas to fix first.

Potassium Intake Calculator: Add Up Potassium-Rich Foods

Add up the potassium in a day of bananas, potatoes, beans, spinach, yogurt and more, and see how far those foods get you toward your daily target.

Resting Heart Rate Analyzer

Rate a resting heart rate against fitness bands for men and women, get Karvonen training zones from it, and see when a reading is worth a doctor visit.

Safe Noise Exposure Time Calculator

How long a noise level is safe before hearing damage starts, on the NIOSH 3 dB rule, and what earplugs or muffs buy you once their NRR is derated.

Sobriety Tracker Calculator

Track sobriety from your clean date - see days, weeks, months, and years sober. Shows recovery milestones at 24 hours, 1 week, 1 month, and 1 year.

Target Heart Rate Calculator

Pick what you are training for and get one target heart rate range for it, in bpm, with the session length, the talk test and the Karvonen arithmetic.

Vitamin B12 Needs Calculator

Estimate daily vitamin B12 needs from age, diet type, and absorption factors. Covers higher needs for vegans, older adults, and people taking metformin.

Vitamin D Sun Exposure Calculator

Estimate sun exposure for vitamin D from Fitzpatrick skin type (I-VI), latitude, and season. Returns midday minutes needed and winter supplement dose.

Zinc Intake Calculator

Find daily zinc intake in mg from age, sex, and diet. Returns RDA and upper limit with top food sources ranked by zinc content for omnivores and vegetarians.

Alcohol Metabolism Calculator

Estimate how long until you are sober based on your weight, drinks consumed, and time drinking. See your estimated BAC over time.

Blood Pressure Category Checker

Enter your systolic and diastolic blood pressure readings to find your category. Covers normal, elevated, high stage 1, stage 2, and crisis.

Body Surface Area (BSA) Calculator

Calculate Body Surface Area using the Mosteller formula. Supports metric and imperial units. Used for medication dosing and clinical assessments.

Caffeine Half-Life Calculator

Calculate how much caffeine remains in your body over time. See when caffeine levels drop low enough for a good night of sleep.

Daily Water Intake Calculator

Calculate daily water intake from body weight, activity level, and climate. Results in liters, fluid ounces, and glasses, with pregnancy and heat adjustments.

Infant Growth Percentile Tracker

Weight and length percentiles from birth to 24 months on the WHO growth standards (official LMS tables) for boys and girls, in metric or imperial units.

IVF Due Date Calculator

Estimate your due date from an IVF embryo transfer: Day 3, Day 5 or Day 6 blastocyst, fresh or frozen, with the equivalent LMP and trimester dates.

Lean Body Mass Calculator

Calculate lean body mass from body fat percentage, tape measurements (Navy method), or the Boer formula. Shows fat mass, lean mass, and a muscle estimate.

Medication Dosage by Weight Calculator

Calculate the correct medication dosage based on body weight using mg/kg dosing. Supports adults and children in metric and imperial units.

One Rep Max (1RM) Calculator

Estimate your one-rep max from the weight and reps you lifted. Uses the Epley formula to calculate your maximum strength for any exercise.

Pregnancy Due Date Calculator

Calculate your estimated due date from your last menstrual period. See your current week, trimester, and key pregnancy milestones.

Sleep Cycle Calculator

Find the optimal bedtime or wake time based on 90-minute sleep cycles. Wake up feeling refreshed by timing your sleep correctly.

VO2 Max Calculator

Estimate VO2 max from a Cooper 12-minute test or a recent race, using the full Daniels VDOT method. Classified against Cooper Institute norms by age and sex.

Allergy Season Calculator

Check expected tree, grass, and weed pollen by US region and month. Returns peak dates, outdoor risk level, and prevention tips for hay fever sufferers.

Blood Type Compatibility Calculator

Find blood donation and transfusion compatibility for all ABO and Rh types. Shows O- as universal donor, AB+ as universal recipient, and full chart.

BMI Formula Calculator

Calculate Body Mass Index in metric (kg and cm) or imperial (lb and inches). Shows the formula worked out with your own numbers, plus your WHO category.

BMI Goal Weight Calculator

Find the weight that matches any target BMI for your height, how far it is from your weight today, and how many weeks it takes at 1 to 2 lbs a week.

Calcium Intake Calculator: Add Up Your Daily Calcium

Add up the calcium in what you eat in a day, from milk, yogurt, cheese, tofu, greens and supplements, and see it against your target and the upper limit.

Daily Calorie Need

Estimate daily calorie needs using the Mifflin-St Jeor formula from age, gender, height, weight, and activity. Returns loss, maintenance, and gain targets.

Glasses Prescription Converter

Convert glasses prescription between plus and minus cylinder notation. Transpose sphere, cylinder, and axis values to match any optician or retailer format.

Intermittent Fasting Timer Calculator

Calculate your eating window and fasting end time from last meal time and protocol. Supports 16:8, 18:6, 20:4, and OMAD intermittent fasting schedules.

Menstrual Cycle / Period Tracker Calculator

Estimate your next period date, PMS window, and fertile window based on your last period and cycle length. A simple planning tool.

Pace Converter Calculator

Convert running pace between min/km, min/mile, km/h, and mph. Enter any format to see all speed and pace equivalents for training zone and race planning.

Posture Break Reminder Calculator

Build a desk break schedule from your work hours and desk type: 20-20-20 eye breaks, a movement break every 30 minutes, and longer breaks.

Screen Viewing Distance Calculator

Find the right viewing distance for a TV, monitor, or phone from its size and resolution, and the distance at which 4K or 1080p pixels disappear.

Shoe Replacement Calculator

Estimate when running shoes need replacing from weekly mileage and shoe type. Adjusts the 300-500 mile guideline for body weight, surface, and rotation.

Standing Desk Timer Calculator

Plan a sit-stand schedule from your hours, ratio, and cycle length. Includes an honest calorie figure based on measured energy expenditure.

Step Length Calculator

Estimate step and stride length from height and gender. Use these values to calibrate your pedometer or GPS watch for more accurate distance and step tracking.

Stretching Routine Calculator

Generate a stretching routine from target body areas and available time. Returns named stretches, hold duration in seconds, repetitions, and total time.

Supplement Cost Calculator: Cost per Day, Month, and Year

Work out what a supplement costs per serving, per day and per year, how long one bottle lasts, and the cost per unit of active ingredient.

TDEE by Activity Calculator

Calculate your Total Daily Energy Expenditure separately for rest days and training days, in metric or imperial. Tailored calorie targets for each.

Vitamin C Daily Need Calculator

Find recommended Vitamin C intake from age, sex, and smoking status per NIH. Returns RDA, tolerable upper limit, food source rankings, and supplement guidance.

Water Bottle Refills Calculator: Hit Your Daily Goal

How many times do you need to refill your bottle to hit your daily water goal? Enter your bottle size and target intake to find out.

20-20-20 Rule Timer Calculator

Plan screen breaks using the 20-20-20 rule to reduce digital eye strain. Enter daily screen hours to get break reminders and total rest time recommendations.

A1C to Blood Sugar Calculator

Convert A1C percentage to estimated average glucose (eAG) in mg/dL and mmol/L. See how your A1C compares to normal, prediabetes, and diabetes ranges.

Adjusted Body Weight Calculator

Calculate adjusted body weight (ABW) for drug dosing in obese patients. Used in anesthesia and pharmacology for accurate medication calculations.

Alcohol Units Calculator

Calculate UK alcohol units in beer, wine and spirits from ABV and volume, see US standard drinks, and compare with the 14-unit weekly UK guideline.

Antibiotic Schedule Calculator

Generate a complete antibiotic dosing schedule with times and end date based on doses per day, start time, and course length.

BMI Calculator

Calculate BMI in metric (kg and cm) or imperial (lb and inches). Returns WHO classification, healthy weight range for your height, and a visual scale.

Body Fat Calculator (US Navy Method)

Estimate body fat using the US Navy method from neck, waist, and hip measurements in metric or imperial. Returns fat %, lean mass, and visual gauge.

Body Frame Size Calculator

Determine your body frame size (small, medium, or large) using wrist circumference and height. Helps interpret ideal weight ranges.

Breast Milk Storage Duration Calculator

Find safe storage times for expressed breast milk at room temperature, in the refrigerator, or in the freezer based on CDC guidelines.

Calorie Calculator (TDEE)

Calculate BMR and TDEE in metric or imperial. Find daily calories for weight loss, maintenance, or muscle gain, with a macro breakdown estimate.

Calorie Deficit Calculator

Calculate the daily calorie deficit needed to reach your target weight in your desired timeline. Safe and sustainable weight loss planning.

Calories Burned Walking Calculator

Calculate calories burned walking from body weight, distance, and pace using MET values (slow 2.8, brisk 4.3, fast 5.0). Returns kcal, time, and steps.

Carb Counter Calculator

Look up total carbs, fiber and net carbs for 15 common foods by serving size in grams, checked against keto, low-carb, ADA per-meal or label targets.

Cholesterol Ratio Calculator

Calculate your cholesterol ratios including Total/HDL, LDL/HDL, and triglyceride ratios for cardiovascular risk assessment.

Corrected Calcium Calculator

Correct serum calcium for low albumin with the Payne equation in mg/dL or mmol/L, and see why 2026 lab guidance prefers total or ionised calcium.

Creatinine Clearance Calculator (Cockcroft-Gault)

Calculate creatinine clearance using the Cockcroft-Gault equation. Estimates kidney function for medication dosing. Supports metric and imperial units.

Daily Fiber Intake Calculator

Calculate daily fiber intake from age, sex, and calorie needs per USDA guidelines. Returns target, current deficit, and top food sources to close the gap.

Daily Iron Intake Calculator

Find daily iron intake in mg from age, sex, pregnancy status, and diet type. Returns NIH RDA, top food sources by mg per serving, and absorption tips.

Daily Steps to Distance Calculator

Convert daily steps to distance in km or miles using your height. Shows stride length, steps per mile, calories burned at your pace, and steps per 5K or 10K.

GFR Calculator (Kidney Function)

Estimate glomerular filtration rate (eGFR) using the CKD-EPI equation. Enter age, serum creatinine, and sex to assess kidney function stage.

Healthy Weight Range Calculator

Find your healthy weight range from height using the BMI 18.5 to 25 band. Shows every category threshold in both pounds and kilograms, plus where you sit.

Hearing Age Calculator

Turn a tone test result into a hearing age. Enter the highest frequency you can still hear in Hz and see how far ahead or behind your actual age it sits.

Hydration Check Calculator

Check your hydration status from urine color, activity level, and temperature. Get a clear reading plus how much extra water to drink for exercise and heat.

Ideal Weight Calculator

Calculate ideal body weight from the Devine, Robinson, and Miller formulas, plus the healthy BMI weight range for your height. Metric and imperial.

IV Drip Rate Calculator

Calculate IV drip rate in drops per minute from volume, infusion time, and drop factor. Supports macro (10-20 gtts/mL) and micro drip (60 gtts/mL) sets.

Macro Calculator

Calculate daily protein, carbohydrate, and fat targets from your TDEE, fitness goal, and preferred diet type. Supports cut, bulk, maintain, and keto macros.

Medical Unit Converter

Convert lab results between mg/dL and mmol/L or µmol/L: glucose, cholesterol, triglycerides, creatinine and uric acid, each with its own factor.

Medication Reminder Calculator

Calculate evenly spaced medication times from dose count per day and first dose time. Returns exact schedule for 2, 3, 4, or 6 daily doses.

Metabolic Age Estimator

Estimate metabolic age from body fat or BMI against the healthy range for your age, plus activity level. Shows your BMR and what actually moves the number.

Normal Blood Sugar Levels by Time of Test

Enter a glucose reading and when you took it. See the normal, pre-diabetes and target ranges for that exact moment, in mg/dL and mmol/L, pregnancy included.

Pediatric Dose Calculator

Calculate pediatric doses by weight or age using Clark's Rule and Young's Rule. Enter adult dose and child data for safe pediatric medication dosing.

Pre-Pregnancy BMI & Weight Gain Calculator

Calculate pre-pregnancy BMI and IOM-recommended gestational weight gain range by category: underweight, normal, overweight, and obese in lbs and kg.

Pregnancy Weight Gain Calculator

Calculate recommended pregnancy weight gain from pre-pregnancy BMI and current week, for one baby or twins, per the IOM 2009 guidelines that ACOG follows.

Protein Need Calculator

Calculate daily protein in grams from body weight, activity, and goals. Returns targets per kg and lb for sedentary, active, and muscle-building routines.

Running Pace for Each Heart Rate Zone

Find the running pace that matches each heart rate zone. Enter max and resting heart rate plus a recent race, and get a pace range per zone.

Senior BMI Calculator

Calculate BMI for adults 65 and over using age-adjusted ranges. Standard charts flag seniors too early, so this one uses the 22 to 27 healthy band.

Sick Day Fluid Intake Calculator

Daily fluid target when ill, from body weight, fever level, and vomiting or diarrhoea episodes. Shows the full breakdown and an hourly pace to drink at.

Sleep Need Calculator

How much sleep you need by age and training load. National Sleep Foundation ranges for all nine age bands, from newborns through older adults.

Smoking Cost Calculator

Calculate how much you spend on cigarettes daily, monthly, and yearly. See your potential savings over 10 years if you quit.

Sodium Intake Tracker

Add up daily sodium from common foods and compare it against the AHA, WHO, or US Dietary Guidelines figure. See your tier and where to cut.

SpO2 to PaO2 Calculator (Oxygen Dissociation Curve)

Estimate arterial oxygen pressure (PaO2) from a pulse oximeter SpO2 with the Severinghaus curve, plus the S/F ratio and a P/F estimate on oxygen.

Steps Goal Calculator

Calculate the daily step increase needed to reach your target steps within a set number of days. Track your walking progress.

Sunscreen Amount Calculator

Work out sunscreen for a whole day from your height, weight and what you are wearing. Uses Du Bois body surface area at the 2 mg/cm² lab standard.

Teen BMI Percentile Calculator

BMI-for-age percentile for teenagers 13 to 19 on the CDC's own growth chart tables, with the healthy weight range for their height and sex.

Time to Sober Calculator

Estimate hours until blood alcohol content (BAC) reaches 0.00 from current BAC level. BAC drops approximately 0.015 per hour regardless of food or coffee.

Vision Prescription Converter

Convert glasses prescription to contact lens Rx with vertex distance adjustment. Adjusts sphere power for myopia, hyperopia, and astigmatism corrections.

Vitamin D Calculator

Find your daily vitamin D target by age, see whether the sun can make any at your latitude and season, and compare food sources with the 4,000 IU limit.

Waist-to-Hip Ratio Calculator

Calculate waist-to-hip ratio (WHR) against the WHO cut-offs of 0.90 for men and 0.85 for women, with a waist-only second reading, in inches or cm.

Walking Speed Estimator

Calculate walking speed in mph, km/h and m/s from distance and time. Compares your gait speed against clinical cutoffs and the median for your age.