How to Use
- Enter basic info
Select your gender and enter your height (cm) and weight (kg).
- Enter measurements
Measure and input your waist, neck, and hip (for women) circumferences in centimeters.
- View results
See your estimated body fat percentage and body fat category.
What is body fat percentage?
Body fat percentage expresses the weight of fat tissue as a proportion of your total body weight. Two people at the same weight can be in very different health, depending on how much is muscle versus fat, so it reflects body composition far more accurately than BMI, which looks only at height and weight.
Fat is not inherently bad — it includes essential fat that the body needs for hormone production, organ protection, and temperature regulation. Because of this, men physiologically require about 3–5% and women about 10–13% body fat.
- Setting diet goals: it lets you focus on losing fat while preserving muscle, not just dropping weight.
- Assessing health risk: excess visceral fat is directly linked to diabetes, high blood pressure, and cardiovascular disease.
- Tracking training results: even when the scale doesn't move, you can confirm whether fat went down and muscle went up.
Calculation formula
This calculator uses the U.S. Navy circumference method, which needs only a tape measure. The equation differs by sex.
Men: %BF = 86.010 × log10(waist − neck) − 70.041 × log10(height) + 36.76
Women: %BF = 163.205 × log10(waist + hip − neck) − 97.684 × log10(height) − 78.387
All circumferences and height are in centimeters and log10 is the base-10 logarithm. For example, a man who is 175 cm tall with an 85 cm waist and 38 cm neck gets 86.010 × log10(85 − 38) − 70.041 × log10(175) + 36.76 ≈ 23.5%.
If you enter your weight, the tool also splits it into fat and lean mass using fat mass = weight × (body fat % ÷ 100) and lean mass = weight − fat mass.