Body Fat Calculator
Estimate your body fat percentage from height, neck, waist and (for women) hip measurements using the U.S. Navy circumference method.
Result
Enter your values and select Calculate to see the result.
How to use this calculator
- Choose the sex used by the formula and your units.
- Measure with a flexible tape, snug but not compressing the skin. Take each measurement two or three times and use the average.
- Men: waist at the navel. Women: waist at the narrowest point and hips at the widest point.
- Add your weight to see fat mass and lean mass.
Formula
U.S. Navy formula (Hodgdon and Beckett), measurements in cm:
- Men:
495 ÷ (1.0324 − 0.19077 × log₁₀(waist − neck) + 0.15456 × log₁₀(height)) − 450 - Women:
495 ÷ (1.29579 − 0.35004 × log₁₀(waist + hip − neck) + 0.221 × log₁₀(height)) − 450
Inch measurements are converted to centimeters first.
Worked example
A man, 180 cm
Neck 40 cm and waist 90 cm give about 18.4% body fat, in the “average” range for men.
Assumptions and limitations
- Tape-measure estimates are typically within about 3–4 percentage points of laboratory methods such as DEXA, and depend on careful measuring.
- Categories follow American Council on Exercise ranges for adults.
- Not suitable for children or during pregnancy. This is not a medical assessment.
Frequently asked questions
How accurate is the Navy method?
It is a reasonable estimate for most adults but can be less accurate for very muscular people or those with unusual fat distribution. Track changes over time rather than relying on a single reading.
What is a healthy body fat percentage?
Ranges vary with age and sex. As a rough guide for adults, about 14–24% for men and 21–31% for women is common for fitness to average categories.