Body Fat Calculator
Estimate your body fat percentage using the US Navy tape method or the quicker BMI method, then see where you land for your age and sex.
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Enter your details and tap Calculate to see your results appear here.
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What Body Fat Percentage Measures
Body fat percentage tells you how much of your weight is fat versus everything else, meaning muscle, bone, water, and organs. Two people at the same BMI can carry very different amounts of fat, so this number adds the detail BMI misses.
Some fat is vital. Essential fat protects organs and supports hormones. Trouble starts when stored fat climbs past healthy limits, since excess fat raises the risk of heart disease and type 2 diabetes.
The US Navy method uses a tape measure and a few circumferences. Quick and free, it lands within a few points of a clinical scan for most people.
How to Use This Calculator
- Pick the US Navy method for accuracy or the BMI method for speed.
- Select your sex and enter your age and height.
- Measure your neck and waist with a tape, and your hips too if you selected female.
- Tap Calculate to see your body fat percentage and category.
The Formula Used
Women: BF% = 495 / (1.29579 − 0.35004·log10(waist + hip − neck) + 0.22100·log10(height)) − 450
- waist, neck, hip
- Circumference measurements in centimetres.
- height
- Standing height in centimetres.
The BMI method uses the Deurenberg equation: BF% = 1.20·BMI + 0.23·age − 10.8·sex − 5.4, where sex is 1 for men and 0 for women.
Understanding Your Results
Tips to Lower Body Fat
- Eat at a small calorie deficit, around 300 to 500 calories below maintenance.
- Lift weights to keep muscle while fat drops.
- Hit 1.6 to 2.2 grams of protein per kilogram of body weight each day.
- Add two or three brisk cardio sessions a week.
- Sleep seven to nine hours, since short sleep raises fat-storing hormones.
Why body fat tells more than weight
Scales miss the line between muscle and fat. Two people at one weight can look and perform worlds apart. Body fat percentage closes that gap by showing what your weight is built from, which makes it a sharper guide for health and training than weight by itself.
Build a fuller picture with partner tools. Gauge muscle through the FFMI Calculator and the Lean Body Mass Calculator, read overall shape with the Body Roundness Index, and cross check the basics on the BMI Calculator.
Healthy ranges and how to improve
Targets shift by sex and age. Many men sit healthiest near 10 to 20 percent, while many women land around 18 to 28 percent, and trained athletes often run lower. Essential fat guards organs and hormones, so chasing very low numbers carries real risk. For a clear reference, the American Council on Exercise body fat chart helps.
Lower the figure with patient habits, not crash plans. Keep protein high, lift to protect muscle, and hold a modest deficit set by your TDEE. Dig deeper in our guide to body composition beyond BMI.
Frequently Asked Questions
The US Navy tape method beats the BMI method because it accounts for where you carry fat. Both are estimates and run a few points off a DEXA scan.
Wrap the tape around the narrowest point for women and at the navel for men, kept level and snug without squeezing.
Yes. Dropping below essential fat, roughly 3% for men and 12% for women, harms hormones, mood, and immune function.
Scientific References
- Hodgdon, J. A., & Beckett, M. B. (1984). Prediction of percent body fat for U.S. Navy men and women from body circumferences and height. Naval Health Research Center.
- Deurenberg, P., Weststrate, J. A., & Seidell, J. C. (1991). Body mass index as a measure of body fatness. British Journal of Nutrition, 65(2), 105–114.
- American Council on Exercise. (2024). Percent Body Fat Norms. ACE Fitness.