Ideal Body Weight Formula (Devine)
Estimate ideal body weight using the Devine formula.
Separate calculations for men and women using height in inches or centimetres.
The Formula
Imperial (height in inches)
Men:
Women:
Metric (height in cm)
Convert height to inches first: inches = cm ÷ 2.54
Then apply the formula above.
The Devine formula was originally developed in 1974 for calculating drug dosages.
It became widely used as a general estimate of ideal body weight.
It applies to adults who are at least 5 feet (152.4 cm / 60 inches) tall.
Variables
| Symbol | Meaning |
|---|---|
| IBW | Ideal Body Weight (kilograms, kg) |
| height | Height in inches (1 inch = 2.54 cm) |
| 50 / 45.5 | Base weight for a person who is 5'0" (men / women) |
| 2.3 | Additional kg per inch above 5'0" |
Example 1 (Men, Imperial)
A man is 5'11" (71 inches / 180.3 cm). What is his ideal body weight?
IBW = 50 + 2.3 × (71 - 60)
IBW = 50 + 2.3 × 11
IBW = 50 + 25.3
IBW = 75.3 kg (about 166 lbs)
Example 2 (Women, Metric)
A woman is 168 cm tall. What is her ideal body weight?
Convert to inches: 168 ÷ 2.54 = 66.14 inches
IBW = 45.5 + 2.3 × (66.14 - 60)
IBW = 45.5 + 2.3 × 6.14
IBW = 45.5 + 14.12
IBW = 59.6 kg (about 131 lbs)
When to Use It
Use the Devine formula when you need to:
- Get a quick estimate of a healthy weight based on height
- Set a general weight goal as a starting point
- Compare against other weight estimation methods
This formula does not account for body frame size, muscle mass, or age.
It tends to give lower estimates for tall individuals.
For a more complete assessment, combine with BMI, body fat percentage, and waist measurements.
This formula is for general educational purposes only. It is not medical advice. Consult a healthcare professional for personalised weight guidance.