What next?
Body fat percentage says more than weight alone. Here is what to do with it.
How to use this calculator
- Pick your sex and enter your height.
- Measure and enter your neck and waist (and hip for women).
- Read your estimated body fat percentage.
What your result means
The percentage estimates how much of your weight is fat, using the US Navy tape method. It is a useful low-cost guide but less precise than a DEXA scan, so measure at the same spots each time. Healthy ranges differ by sex and age.
Why this one is different
The US Navy tape method is named up front, along with the honest accuracy range — this is an estimate from three tape measurements, not a DEXA scan, and the page says so rather than presenting a decimal as fact. Nothing you measure leaves your browser.
Why two people at the same weight can look completely different
The scale measures everything — muscle, bone, water and fat — in one blunt number. Body fat percentage tells the more useful story: how much of you is actually fat. It’s why someone can "gain weight" while getting leaner.
The US Navy tape method used here needs nothing but a tape measure, and tracking the trend over weeks matters far more than obsessing over a single reading.
How it works
The US Navy method estimates body fat from circumference measurements — neck and waist for men, plus hips for women — combined with height. It's surprisingly accurate for a no-equipment method, though calipers or a DEXA scan are more precise. Measure with a snug, level tape and no clothing over the area.
Formula (men)
Example calculation
A man with waist 90 cm, neck 40 cm, height 178 cm:
= 1.0324 − 0.3241 + 0.3478 = 1.0561
%BF = 495 ÷ 1.0561 − 450 = 18.7%
Frequently asked questions
How accurate is the tape method?＋
Within a few percentage points for most people. Consistent measuring technique matters more than the exact tool — track the trend over time rather than a single number.
Where exactly do I measure?＋
Neck below the larynx, waist at the navel, hips at the widest point. Keep the tape horizontal and don't pull it tight.
Which method is this based on?＋
The US Navy circumference method, which estimates body fat from height and tape measurements at the neck, waist and, for women, hips. It needs no equipment beyond a tape measure.
What is a healthy body fat percentage?＋
Commonly cited fitness ranges are roughly 14-24 percent for men and 21-31 percent for women, with athletes often lower. These are guides, not clinical thresholds.
How often should I re-measure?＋
Every two to four weeks. Body fat changes slowly, and tape measurements carry enough error that shorter intervals mostly show measurement noise rather than real change.
Why does the result differ from my smart scale?＋
Bioimpedance scales infer fat from how easily a current passes through the body, which shifts with hydration, food and time of day. The tape method has different biases again. Pick one method and track its trend.
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Assumptions & limitations
Every figure here comes from a simplified model. Keep these limits in mind when reading your result:
- Uses the U.S. Navy circumference method — an estimate, usually within ~3–4% of a DEXA scan.
- Accuracy depends on measuring at the right spots with the tape snug but not tight.
- Not intended for use during pregnancy.