Body Fat Calculator.
Estimate your body fat percentage with the US Navy tape method - no calipers, scales, or scans needed. Enter your sex, height, neck, and waist (plus hip for women) and get your body fat percentage plus a category label in seconds.
Calculate your body fat
Tip: for the Navy method, waist must be larger than neck (and waist + hip larger than neck for women), or the formula cannot resolve.
the short answer
The US Navy body fat formula is: men, BF% = 495 / (1.0324 - 0.19077 x log10(waist - neck) + 0.15456 x log10(height)) - 450; women, BF% = 495 / (1.29579 - 0.35004 x log10(waist + hip - neck) + 0.22100 x log10(height)) - 450, all in centimetres. It needs only a tape measure - no scale, calipers, or scans.
What is the Navy body fat calculator and how is it calculated?
Your body fat percentage is the share of your total body weight that is fat, as opposed to muscle, bone, organs, and water. It is a far more useful health and progress marker than scale weight alone, because two people at the same weight can carry very different amounts of fat. The Navy body fat calculator estimates that percentage from a handful of circumference measurements instead of an expensive scan.
The method comes from the US Navy and uses a logarithmic regression. For men the formula is BF% = 495 / (1.0324 - 0.19077 x log10(waist - neck) + 0.15456 x log10(height)) - 450. For women it adds the hip measurement: BF% = 495 / (1.29579 - 0.35004 x log10(waist + hip - neck) + 0.22100 x log10(height)) - 450. Every measurement is in centimetres - if you enter imperial inches, the tool multiplies each value by 2.54 to convert to centimetres before running the formula, so the math is identical either way.
The biggest advantage is that it needs no equipment beyond a soft tape measure - no calipers, no bioimpedance scale, no DEXA appointment. That makes it cheap to repeat, which matters more than a single perfect reading. The trade-off is that it is an estimate: it works from your shape, not a direct fat measurement, so measure the same way each time and watch the trend.
Body fat percentage categories by sex.
The result panel labels your number against these general ranges. Women carry more essential fat than men, so the healthy bands sit higher - the same percentage means something different for each sex.
| Category | Men | Women |
|---|---|---|
| Essential fat | 2 - 5% | 10 - 13% |
| Athlete | 6 - 13% | 14 - 20% |
| Fitness | 14 - 17% | 21 - 24% |
| Average | 18 - 24% | 25 - 31% |
| Obese | 25%+ | 32%+ |
These bands are general guidance, not a medical diagnosis. To pair body fat with a calorie plan, run your numbers through our TDEE calculator and BMR calculator.
How coaches use a body fat calculator.
For online fitness and nutrition coaches, the Navy tape method is the cheapest reliable progress check between scans. The workflow is simple: record neck, waist, and hip at each check-in, estimate body fat the same way every time, and watch the trend rather than reacting to one reading. Because it needs no equipment, every client can do it at home and report back - which keeps progress visible even when the scale stalls during recomposition.
The harder part is keeping those measurements attached to a real plan rather than scattered across notes. If you coach clients online, our guides on how to become an online fitness coach and how to price your coaching packages are the next steps once your measurement method is set.
Track measurements like this for every client.
A calculator gives you one reading. Coachway lets coaches set per-client targets and track check-in measurements alongside training and nutrition in one place, so a tape number turns into a trend your clients follow in their own branded app. See how the meal planner handles the nutrition side.
See Coachway pricingFrequently asked questions.
What is a body fat calculator?
A body fat calculator estimates your body fat percentage from a few tape measurements instead of a scale weight. This one uses the US Navy tape method, which takes your sex, height, neck, and waist (plus hip for women) and runs them through a logarithmic formula. It needs no calipers, scans, or special equipment - just a soft tape measure.
What is the formula for the Navy body fat calculator?
The US Navy body fat formulas are: for men, BF% = 495 / (1.0324 - 0.19077 x log10(waist - neck) + 0.15456 x log10(height)) - 450; for women, BF% = 495 / (1.29579 - 0.35004 x log10(waist + hip - neck) + 0.22100 x log10(height)) - 450. All measurements are in centimetres - imperial inches are converted by multiplying by 2.54 first.
How accurate is the Navy body fat method?
The Navy tape method is typically within 3 to 4 percent of a DEXA scan for most people, which is good for a no-equipment estimate. Accuracy drops at the extremes - very lean or very heavy bodies - and depends on measuring at the right spots. Use it to track change over time rather than as a single exact number, and always measure the same way each time.
Where do I measure my neck, waist, and hips?
Measure your neck just below the larynx with the tape sloping slightly down at the front. Men measure the waist at the navel; women measure the waist at its narrowest point and the hips at the widest point of the glutes. Keep the tape snug but not compressing the skin, stand relaxed, and breathe out normally before reading.
What is a healthy body fat percentage?
General ranges differ by sex. For men, roughly 2 to 5 percent is essential, 6 to 13 percent is athletic, 14 to 17 percent is fitness, 18 to 24 percent is average, and 25 percent or more is in the obese range. For women the bands sit higher: 10 to 13 percent essential, 14 to 20 percent athletic, 21 to 24 percent fitness, 25 to 31 percent average, and 32 percent or more obese.
How do coaches use a body fat calculator?
Coaches use the Navy tape method as a cheap, repeatable progress check between scans. They record neck, waist, and hip measurements at each check-in, estimate body fat the same way every time, and watch the trend rather than one reading. On a coaching platform like Coachway, those measurements and targets sit per client alongside training and nutrition, so a tape number becomes part of an actual plan.
This calculator is general information, not medical or dietary advice. The Navy tape method is an estimate, not a substitute for a DEXA scan or guidance from a qualified professional.
Keep going: estimate your resting burn with the BMR calculator and your daily target with the TDEE calculator, or read our guides on becoming an online fitness coach and pricing online coaching packages.
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Open calculator ->See what Coachway can do for your coaching business
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