Body Fat Calculator
This body fat calculator estimates your body fat percentage with the US Navy tape method, so you only need a soft tape measure, no calipers. Enter your height, neck, and waist, plus hips for women, and you'll get your body fat percentage, your category, and how your weight splits into fat and lean mass. It works in metric or imperial.
- US Navy method
- No calipers
- Fat & lean mass
- Category for your sex
- Metric or imperial
Last updated June 17, 2026 Estimates only, not medical advice Reviewed by the Calcowa team
Check your measurements: waist must be larger than neck.
Measure snug and level with a soft tape. A screening estimate, not medical advice.
US Navy tape formula from height, neck, and waist
A tape-based estimate, not medical advice or a lab measurement. Use it to track trends over time.
What is body fat percentage?
Body fat percentage is the share of your weight that's fat, with the rest being lean mass: muscle, bone, organs, and water. It's a more telling number than weight alone, because two people at the same weight can carry very different amounts of fat and muscle. Tracking your body fat percentage shows whether a change on the scale is fat or muscle, which the scale itself can't tell you. It's the number that actually reflects your shape, and that's why athletes and coaches watch it closely.
How do you calculate body fat?
The US Navy method needs only a tape measure. Here's how it works:
- 1
Measure your neck and waistNeck just below the larynx, waist at the navel for men. Women add the hips at the widest point.
- 2
Add your heightThe formula compares your circumferences to your height, so taller frames read differently.
- 3
Apply the Navy formulaA log-based equation turns those measurements into a body fat percentage. The calculator runs it instantly.
- 4
Check your categoryYour percentage lands in a band, from essential and athlete up through fitness, average, and above.
Body fat percentage categories
These are the common American Council on Exercise ranges. Women carry more essential fat than men, so the bands sit higher.
| Category | Men | Women |
|---|---|---|
| Essential fat | 2–5% | 10–13% |
| Athletes | 6–13% | 14–20% |
| Fitness | 14–17% | 21–24% |
| Average | 18–24% | 25–31% |
| Above average | 25%+ | 32%+ |
Body fat versus BMI
BMI is quick, but it only knows your weight and height, so it can't separate muscle from fat. A lean, muscular athlete and an out-of-shape person can share the same BMI while having very different bodies. Body fat percentage looks at the fat directly, which is usually what people really want to know. Using both is the smart move, and you'll get a fuller picture: check your BMI for a fast weight-for-height read, and your body fat here for composition. Once you know your lean mass, the BMR calculator can use it for an even sharper estimate, and the calorie calculator turns it into a plan.
Frequently asked questions
Is the army body fat calculator the same?
It's nearly identical. The US Army uses the same tape measurements and a very similar formula to the Navy one here, with its own pass-or-fail limits by age. The percentage you get above is a close match to either standard.
The US Navy method uses a tape measure instead of calipers. You measure your height, neck, and waist, plus hips for women, and a formula based on those circumferences estimates your body fat percentage. It's the approach this calculator uses, so all you need is a soft tape. It isn't as precise as a lab scan, but it's free, repeatable, and close enough to track progress.
It differs by sex. For men, roughly 14 to 17% is fitness level and 18 to 24% is average; for women it's about 21 to 24% fitness and 25 to 31% average. Below those ranges sits the athlete band, and a small essential-fat floor your body needs to function. The result above places your number on the right scale for your sex.
It's a solid estimate, usually within about 3 to 4 percentage points of a lab measurement for most people. Accuracy rests on careful tape work: keep the tape snug and level, measure the same spots each time, and breathe normally. It's less exact for very lean or very heavy bodies, so you'll get the most from it as a trend tracker rather than a precise reading.
Measure your neck just below the larynx, sloping slightly down to the front, and your waist at the navel for men or at the narrowest point for women. Women also measure the hips at the widest point. Keep the tape level and snug without squeezing, and stand relaxed. Measuring the same way each time matters more than getting it perfect once, so you'll get consistent reads.
BMI compares your weight to your height and can't tell fat from muscle, so a muscular person reads high. Body fat percentage measures the fat itself, which is what most people actually care about. They answer different questions, and using both gives a fuller picture. The BMI calculator covers the weight-for-height side.
Fat mass is your weight that comes from body fat; lean mass is everything else, including muscle, bone, organs, and water. The calculator splits your weight into the two using your body fat percentage. Watching lean mass hold steady while fat mass drops is the sign you're losing fat, not muscle.
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Tracking composition?
Estimate your body fat above, or browse the full health hub.