Body fat percentage calculator
With just a tape measure, estimate your body fat percentage using the US Navy method, plus fat and lean mass and your waist-to-height ratio.
Calculated in your browser and never stored. An estimate, not a medical measurement.
How to measure
- Neck: just below the Adam’s apple, tape sloping slightly down at the front.
- Waist: men at the navel; women at the narrowest point. Relax, don’t suck in.
- Hips (women): at the widest part of the buttocks.
- Measure twice and use the average. Keep the tape snug but not compressing the skin.
Accuracy
The US Navy formula is usually within 3–4 percentage points of lab methods like DEXA for most people, but can be less accurate for very lean or very muscular builds. Track the trend over time rather than any single reading. Waist-to-height ratio is a simple, well-studied marker: keeping your waist under half your height is a good target.
Compare with your BMI and daily calorie estimate.
Frequently asked questions
What is a healthy body fat percentage?
Roughly 14–24% for men and 21–31% for women, depending on age and the source.
Is this more accurate than BMI?
Usually, because it uses body measurements rather than weight alone, so muscular people aren’t misclassified as easily.
Why do I need my weight?
Only for fat and lean mass. The body fat percentage itself comes from height and tape measurements.