Body fat calculator
Estimate your body fat % with the US Navy tape method.
Body fat calculator
Estimate your body fat percentage using the US Navy method, which only needs a tape measure: height, neck and waist (plus hip for women). It also shows your fat mass and lean mass. Everything is calculated in your browser — no measurements leave your device.
How to measure
- Neck: just below the larynx, tape sloping slightly down.
- Waist: at the navel for men, at the narrowest point for women.
- Hip (women): at the widest point.
Formula
The US Navy formula uses logarithms of these circumferences and your height. Men: 495 ÷ (1.0324 − 0.19077·log₁₀(waist − neck) + 0.15456·log₁₀(height)) − 450. Women add the hip measurement. It’s an estimate (±3–4%), not a clinical body-composition scan.
Frequently asked questions
How accurate is the US Navy method? Within about 3–4% for most people — good enough to track changes over time.
What is a healthy body fat percentage? Roughly 10–20% for men and 18–28% for women, varying with age and fitness.