Body Fat Calculator
Estimate your body fat percentage from a few tape measurements with the U.S. Navy method, in inches or centimeters. See your category, fat mass and lean mass.
Free · No sign-upHow to use Body Fat Calculator
- 1. Pick your sex and units (inches and pounds or centimeters and kilograms).
- 2. Enter your height and measure your neck and waist — women also measure the hips. Open “How to measure” for tape positions.
- 3. Add your weight and age (optional) to see fat mass, lean mass and a BMI-based estimate.
- 4. Read your body fat % and ACE category, check the formula with your numbers, then copy the result or share a link.
Frequently asked questions
How accurate is the U.S. Navy body fat method?
Studies usually find tape methods within about 3 to 4 percentage points of lab methods such as DEXA or hydrostatic weighing. Careful, repeated measurements at the same spots matter more than the formula, and trends over time are more useful than a single reading.
What is a healthy body fat percentage?
The American Council on Exercise lists 14–17% as “fitness” and 18–24% as “average” for men, and 21–24% “fitness” and 25–31% “average” for women. Essential fat is about 2–5% for men and 10–13% for women. Talk to a health professional about what is right for you.
Where do I measure my neck, waist and hips?
Measure the neck just below the larynx, the waist at the navel for men or at the narrowest point for women, and the hips around the widest part of the buttocks. Keep the tape level and snug without pressing into the skin, and don’t pull the stomach in.
Why is the BMI-based estimate different?
The BMI method only uses height, weight, age and sex, so it can’t tell muscle from fat. The Navy method uses body measurements and is usually closer for athletic people. The BMI figure is shown only for comparison.
What formula does the calculator use?
For men: 495 ÷ (1.0324 − 0.19077 × log10(waist − neck) + 0.15456 × log10(height)) − 450. For women: 495 ÷ (1.29579 − 0.35004 × log10(waist + hip − neck) + 0.22100 × log10(height)) − 450, with all measurements in centimeters.
Is my data stored or sent anywhere?
No. The calculation runs in your browser. Your last inputs are remembered only on this device so you can come back to them, and a share link contains only the numbers you choose to share.