How to Calculate Body Fat Percentage Without Equipment
Body fat percentage tells you what fraction of your total weight is fat mass. Unlike BMI, it distinguishes between muscle and fat, making it a more meaningful measure of body composition. You can estimate it at home using circumference measurements.
US Navy Circumference Method
This method requires only a soft measuring tape.
Men (measure waist at navel, neck at narrowest point):
Body Fat % = 86.010 × log10(waist − neck) − 70.041 × log10(height) + 36.76
Women (measure waist at narrowest, hips at widest, neck at narrowest):
Body Fat % = 163.205 × log10(waist + hip − neck) − 97.684 × log10(height) − 78.387
(All measurements in inches)
Step-by-Step Example
Male: Height = 70 in, Waist = 34 in, Neck = 15 in
BF% = 86.010 × log10(34 − 15) − 70.041 × log10(70) + 36.76 = 86.010 × log10(19) − 70.041 × 1.8451 + 36.76 = 86.010 × 1.2788 − 129.19 + 36.76 = 109.99 − 129.19 + 36.76 = 17.56%
Healthy Body Fat Ranges
| Category | Men | Women |
|---|---|---|
| Essential fat | 2–5% | 10–13% |
| Athletes | 6–13% | 14–20% |
| Fitness | 14–17% | 21–24% |
| Average | 18–24% | 25–31% |
| Obese | 25%+ | 32%+ |
BMI-Based Estimate (Less Accurate)
A rough estimate using BMI and age (Deurenberg formula):
BF% = (1.2 × BMI) + (0.23 × Age) − (10.8 × Sex) − 5.4
Where Sex = 1 for male, 0 for female.
Use our body fat calculator for the US Navy method calculation.