Navy body fat calculator.
Estimate your body fat percentage with the official US Navy circumference method - the tape test the Navy uses for its own body composition screening. Enter your sex, height, neck, and waist (plus hip for women) and get your body fat percentage, a category label, and lean mass if you add bodyweight. This page covers the tape method specifically - for skinfold, calipers, and other approaches, see our general body fat calculator.
Calculate your Navy 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 Navy body fat calculator estimates your body fat percentage from a few tape measurements, using the US Navy circumference formula: 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 soft tape measure - no scale, calipers, or scans - and lands within about 3 to 4 percentage points of a DEXA scan for most people.
What is the Navy body fat calculator and how does the circumference method work?
The Navy body fat calculator is a specific, well-known way to estimate body fat percentage - the share of your total weight that is fat rather than muscle, bone, organs, and water. It comes from the US Navy, which needed a fast, no-equipment screen it could run on thousands of people, so it built a logarithmic regression that predicts body fat from circumference measurements alone. The same method now shows up everywhere as the "Navy method" or "tape method." This page is the Navy circumference version specifically - if you want skinfold calipers or other approaches, use our general body fat calculator.
The math is fixed. For men the formula is BF% = 495 / (1.0324 - 0.19077 x log10(waist - neck) + 0.15456 x log10(height)) - 450, which is why a bigger waist relative to the neck drives the estimate up. 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 input is in centimetres, so if you enter inches the calculator multiplies each value by 2.54 before it runs the formula - the answer is the same either way.
The big advantage is that it needs no equipment beyond a soft tape measure. That makes it repeatable at almost no cost, which matters more than any single perfect reading. The trade-off is that it works from your shape, not a direct fat measurement, so it is an estimate. If you add bodyweight, the calculator also splits it into lean mass and fat mass - the same math behind our lean body mass calculator.
How to take the tape measurements.
The formula is only as good as the tape work, so the Navy is precise about where the tape goes. Measure your neck just below the larynx, with the tape sloping slightly down toward the front - do not flare it out over the shoulders. Men measure the waist horizontally at the navel; women measure the waist at its narrowest point and add the hip measurement at the widest point of the glutes. Keep the tape snug against the skin but not compressing it, stand relaxed with arms at your sides, and breathe out normally before you read the number.
Two habits protect your trend line. First, take each measurement two or three times and use the average - a single pull of the tape is easy to get slightly wrong. Second, measure under the same conditions every time: same time of day, before eating, and ideally the same person holding the tape. The absolute reading carries a little error no matter what, but a change measured the same way each time is trustworthy. If you would rather track a single tape number with no formula, our waist-to-height ratio calculator is the simplest version of the same idea.
Navy method accuracy vs DEXA, skinfold, and BIA.
Be honest about what a tape estimate can and cannot do. Against a DEXA scan - the practical gold standard for body composition - the Navy circumference method is typically within about 3 to 4 percentage points for the general population. That is close enough to set targets and track direction, but not precise enough to argue over half a percent. The error grows at the extremes: on very lean athletes it tends to over-estimate, and on very heavy bodies the waist term can push it the other way.
Against the other no-lab options, the picture is favourable. Skinfold calipers can be more accurate in a trained tester's hands, but they are much less consistent for beginners, since pinch site and pressure vary from person to person. Bioimpedance (BIA) scales swing with hydration, food, and time of day, so a morning and evening reading can differ by several points. The Navy method's strength is not that it is the most accurate single measure - it is that it is cheap to repeat and hard to bias once you learn the tape points, which is what makes the trend reliable.
What body fat percentage does the Navy allow?
The Navy uses this same circumference method as a pass-or-fail body composition screen, with a maximum allowable body fat. The figures below are the commonly published Navy maximums by age and sex. Treat them as service screening limits, not health goals - and check the current Navy instruction, because the standards have been revised over time, most recently toward a single ceiling near 26% for men and 36% for women.
| Age band | Men (max) | Women (max) |
|---|---|---|
| 17 - 21 | 22% | 33% |
| 22 - 29 | 23% | 34% |
| 30 - 39 | 24% | 35% |
| 40 and over | 26% | 36% |
For general fitness, healthy ranges sit lower and are read as bands rather than a single cutoff. Roughly, men land in a fitness range around 14 to 17% and women around 21 to 24%, with athletic ranges below that - our general body fat calculator lists the full category table by sex. To turn a body fat target into a calorie plan, run your numbers through the TDEE calculator and the FFMI calculator for muscular potential.
Why online coaches use the tape method for remote clients.
For a coach working with clients remotely, the tape method is a natural fit. A client anywhere can take neck, waist, and hip measurements at home with a single tape and send them in - no lab, no calipers, no scale that reads differently than yours. The workflow is simple: record the same measurements at each check-in, estimate body fat the same way every time, and watch the trend rather than reacting to one reading. Because the change between two clean measurements is far more reliable than any single number, it is a solid progress signal even during a body recomposition when the scale barely moves.
The hard part is keeping those measurements attached to a real plan instead of scattered across chat threads and spreadsheets. Inside Coachway, a coach logs each client's check-in measurements next to their training, nutrition, and messages, sets a per-client body fat target, and sees the trend build over time in the client's own branded app. If you are setting up the business side around your measurement method, our guides on becoming an online fitness coach and pricing your coaching packages are the next steps.
Track check-in measurements for your whole client list from one tab.
No charge today - cancel anytime under Billing.Frequently asked questions.
How accurate is the Navy body fat calculator?
The US Navy circumference method is typically within 3 to 4 percentage points of a DEXA scan for most people, which is good for a no-equipment estimate. It is more repeatable than skinfold calipers in untrained hands and steadier than most bioimpedance scales, but less precise than DEXA. Accuracy drops at the extremes - very lean or very heavy bodies - and depends on measuring at the same spots each time. Use it to track change over time rather than as one exact number.
What body fat percentage does the Navy allow?
The Navy sets a maximum allowable body fat for its physical readiness screening, measured with this same circumference method. Commonly published Navy standards run by age from about 22% to 26% for men and about 33% to 36% for women, and recent revisions moved toward a single ceiling near 26% for men and 36% for women. These are pass or fail screening limits for service members, not a health target - always check the current Navy instruction for the exact figures, because they have changed over time.
What is the formula for the Navy body fat calculator?
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. Every measurement is in centimetres - if you enter inches, each value is multiplied by 2.54 first, so the result is identical either way.
How do I measure my neck, waist, and hips for the Navy method?
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 you read it. Measuring the same way every time matters more than any single reading.
Is the Navy body fat calculator good enough for coaching clients?
Yes, for tracking. Because it needs only a tape measure, a remote client can take neck, waist, and hip measurements at home and report them at each check-in. The absolute number carries a few points of error, but the change between two measurements taken the same way is a reliable progress signal - which is exactly what a coach programs from between scans.
This calculator is general fitness information, not medical advice. The US Navy circumference method is an estimate, not a substitute for a DEXA scan or guidance from a qualified professional, and the Navy standards quoted here are screening references that can change - always confirm the current instruction.
Keep going: split your weight into lean and fat mass with the lean body mass calculator, estimate your daily burn with the TDEE calculator, or compare other tape-only markers with the waist-to-hip ratio calculator.
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A calculator gives you one client's number today. Coachway lets a coach set body fat targets and log tape measurements at every check-in, right beside training, nutrition, and messages - so a tape reading becomes a trend your client follows in their own branded app. Start a 14-day free trial and see the whole platform, no charge today, cancel anytime under Billing.
