Body Fat Calculator
Estimate your body fat percentage with just a tape measure, using the U.S. Navy circumference method. See your category, fat mass and lean mass.
Key facts
- The U.S. Navy method estimates body fat from your height and neck and waist measurements (plus hips for women).
- Done carefully, tape methods are usually within about 3 to 4 percentage points of lab tests.
- The number is most useful for tracking change: measure the same way every few weeks.
How to measure
- Neck: just below the Adam’s apple (larynx), with the tape sloping slightly down towards the front.
- Waist: men at the level of the navel; women at the narrowest point, usually a little above the navel. Breathe out normally and don’t suck in.
- Hips (women): around the widest part of the buttocks, feet together.
- Stand straight and relaxed, keep the tape level and snug but not pressing into the skin, and take each measurement twice. Use the average.
The formula
Men: %BF = 495 ÷ (1.0324 − 0.19077 × log10(waist − neck) + 0.15456 × log10(height)) − 450 Women: %BF = 495 ÷ (1.29579 − 0.35004 × log10(waist + hip − neck) + 0.22100 × log10(height)) − 450
All measurements in centimetres. The equations were developed by Hodgdon and Beckett at the U.S. Naval Health Research Center in 1984 and are among the most widely used tape-measure methods.
Body fat categories
| Category | Men | Women |
|---|---|---|
| Essential fat | 2 to 5% | 10 to 13% |
| Athletic | 6 to 13% | 14 to 20% |
| Fit | 14 to 17% | 21 to 24% |
| Average | 18 to 24% | 25 to 31% |
| Above average | 25% or more | 32% or more |
Categories as used by the American Council on Exercise. Women naturally carry more essential fat than men.
Other ways to measure body fat
- DEXA scan: very accurate and also measures bone, but costs money and needs a clinic.
- Smart scales (bioimpedance): quick, but readings swing with hydration, food and time of day.
- Skinfold calipers: good in trained hands, less reliable when you do it yourself.
Know your number? Enter it in the TDEE calculator to use the Katch-McArdle or Cunningham equation, which work from lean body mass.
Track your measurements in the app
Calculators give an estimate. Log your weight and food for two weeks and the TDEE Calculator app works out what your body really burns, then keeps your target up to date.
- Measured TDEE from your own weight trend and food log
- Food diary with 356 everyday foods from around the world and a barcode scanner
- AI coach and photo calories: snap your plate, check the estimate, add it
- 74 languages, metric or US units, Ramadan mode and reminders
- Private: your log stays on your phone. No ads, no trackers
Body fat calculator questions
How accurate is the U.S. Navy body fat method?
For most people it lands within about 3 to 4 percentage points of lab methods like DEXA. It is less accurate for very lean, very muscular or very heavy people, and when measurements are taken differently each time.
What is a healthy body fat percentage?
Roughly 14 to 24% for men and 21 to 31% for women covers the “fit” and “average” categories. Going below the essential fat levels (about 2 to 5% for men, 10 to 13% for women) is unhealthy.
Why do women need their hips measured?
Women store more fat around the hips and thighs, so the women’s equation adds the hip measurement to give a better estimate.
How often should I measure?
Every 2 to 4 weeks is enough. Measure at the same time of day (mornings are best) and in the same way, and look at the trend rather than one reading.
Is body fat better than BMI?
For one person, often yes: it separates fat from muscle, which BMI can’t. The two together, plus your waist size, give a fuller picture.
Sources
- Hodgdon JA, Beckett MB. Prediction of percent body fat for U.S. Navy men and women from body circumferences and height. Naval Health Research Center, San Diego; Reports 84-11 and 84-29, 1984.
- American Council on Exercise. Percent body fat norms for men and women.