Body Fat Calculator
Estimate body fat percentage from body measurements using the U.S. Navy circumference method.
This calculator uses the U.S. Navy circumference method. It is an estimate, not a medical diagnosis.
How this calculator works
How to use this calculator
1. Choose your sex.
2. Select inches or centimeters.
3. Enter your height, neck, and waist measurements.
4. If you choose female, enter hip measurement as well.
5. Optional: enter your weight to estimate fat mass and lean mass.
6. Click Calculate Body Fat to see your estimated result.
Formula used
This calculator uses the U.S. Navy circumference method. Measurements are converted to inches before calculation.
Men:
Body fat % = 86.010 × log10(waist − neck) − 70.041 × log10(height) + 36.76
Women:
Body fat % = 163.205 × log10(waist + hip − neck) − 97.684 × log10(height) − 78.387
If weight is entered, fat mass is calculated as weight × body fat percentage, and lean mass is calculated as weight − fat mass.
Example calculation
Example for a male with height 70 in, waist 34 in, and neck 15 in:
Body fat % = 86.010 × log10(34 − 15) − 70.041 × log10(70) + 36.76
Estimated body fat = 17.5%
Example for a female with height 65 in, waist 30 in, hip 40 in, and neck 13 in:
Estimated body fat = 31.1%
What the result means
The result is an estimate of body fat percentage based on tape measurements. It is useful for tracking changes over time when you measure consistently. It is not as precise as a clinical body composition test such as DEXA, and it should not be used as a medical diagnosis.
Frequently asked questions
Is this body fat calculator accurate?
It provides an estimate based on the U.S. Navy circumference method. Results can vary depending on measurement technique, body shape, and hydration, so use it mainly for tracking trends over time.
Why does the female formula ask for hip measurement?
The U.S. Navy formula for women uses waist, hip, neck, and height because body fat distribution differs between men and women.
Can I use centimeters?
Yes. The calculator accepts centimeters and converts them internally before applying the formula.
Should I enter my weight?
Weight is optional. It is only used to estimate fat mass and lean mass after the body fat percentage is calculated.