Macro Calculator

Macros is short for macronutrients, the three categories of food that supply calories: protein, carbohydrates, and fat. Alcohol is a fourth source of calories but is not a nutrient, which is why it never appears in a macro split.

This calculator splits your daily calorie target into grams of each macro, based on your goal and diet style.

How It Works

Step 1. Adjust calories for your goal:

Target Calories = TDEE × Goal Multiplier

TDEE stands for Total Daily Energy Expenditure, your daily calorie burn including activity. The TDEE calculator linked below works it out if you do not have the number.

Step 2. Split calories by macro ratio. Each diet style has different percentages:

Step 3. Convert calories to grams using the calorie value of each macro:

• Protein: 4 kcal per gram → grams = (target cal × protein %) ÷ 4
• Carbs: 4 kcal per gram → grams = (target cal × carbs %) ÷ 4
• Fat: 9 kcal per gram → grams = (target cal × fat %) ÷ 9

The Protein Minimum

The best single source here is a 2018 meta-analysis of 49 training studies by Morton and colleagues. Muscle gains stopped improving at about 1.6 g of protein per kg of body weight a day, which is 0.73 g per lb, and the top of their estimate was 2.2 g per kg, or 1.0 g per lb. For someone at 150 lb that is 110 to 150 g a day. The calculator checks your split against the 0.7 g per lb end of that.

Cutting is the one time to aim higher, because a deficit makes the body more willing to spend muscle for fuel. Helms and colleagues (2014) put lean lifters in a deficit at 2.3 to 3.1 g per kg of lean mass. That is why high-protein splits like 40/30/30 tend to beat a balanced 30/40/30 for fat loss.

Worked Example

30-year-old woman, 145 lb, moderate activity, TDEE = 2,100 kcal. Goal: lose weight. Diet: balanced (30/40/30).

• Target: 2,100 × 0.80 = 1,680 kcal
• Protein: 1,680 × 0.30 ÷ 4 = 126 g (0.87 g per lb, which clears the minimum)
• Carbs: 1,680 × 0.40 ÷ 4 = 168 g
• Fat: 1,680 × 0.30 ÷ 9 = 56 g

Spread across 3 meals, that’s 42 g protein, 56 g carbs, and 19 g fat per meal. About a chicken breast, a cup of rice, and a tablespoon of oil per meal.

Picking a Diet Style

• Balanced is a safe default if you don’t have a strong reason to deviate. Easy to follow long-term.
• High-protein is what most fitness coaches recommend for fat loss. Higher satiety, better muscle retention.
• Low-carb can work well for people who feel bloated on high carbs, or who prefer fewer/larger meals.
• Ketogenic is highly restrictive, under 50 g of carbs a day. Real benefits for some people (epilepsy, certain metabolic conditions), but not magic for general fat loss. Hard to sustain socially. The keto option here is a plain 25/5/70 split; the keto macro calculator linked below sets protein from your lean mass instead, which is the better way to plan keto and usually lands nearer 30% protein.

The best diet is the one you’ll actually stick with. Macro percentages matter far less than total calories and total protein.