Body Fat Calculator
Free body fat calculator using the US Navy circumference method: estimate body-fat percentage from height, neck, waist (and hip) measurements.
updated
- ✓ Runs in your browser — nothing uploaded
- ✓ No sign-up
- ✓ Free, no limits
US Navy tape method — typically within a few points of a DEXA scan. Best used to track your own trend; not medical advice.
This body-fat calculator estimates your body-fat percentage from tape measurements — no calipers, no scan. It uses the US Navy circumference method: height and neck and waist for men, plus hip for women, fed into the published Hodgdon–Beckett equations the military still uses for fitness assessments.
Measure the neck just below the larynx, the waist at the navel (for men) or the narrowest point (for women), and the hip at the widest point, tape snug but not compressing. Worked example: a man of 180 cm with a 38 cm neck and 85 cm waist comes out around 16% — in the ACE 'fit' band, which the calculator also reports.
A tape estimate is honest about being an estimate: it typically lands within a few percentage points of a DEXA scan, better for tracking your own change over time than for one-off precision. Measure at the same time of day under the same conditions, and read the trend, not a single decimal. Your measurements never leave your browser.
Frequently asked questions
How accurate is the Navy tape method?
Studies put it within roughly 3–4 percentage points of lab methods like DEXA for most people. Its real strength is consistency: measured the same way over weeks, it tracks change in body composition well.
What is a healthy body-fat percentage?
ACE bands: men — 6–13% athlete, 14–17% fit, 18–24% average; women — 14–20% athlete, 21–24% fit, 25–31% average. Women carry more essential fat by design; the two scales are not comparable.
Where exactly do I measure?
Neck: just below the Adam's apple, tape sloping slightly down at the front. Waist: at the navel for men, narrowest point for women, after a normal exhale. Hip (women): the widest point. Snug tape, no compression.
Is anything uploaded?
No — the equations run in your browser and your measurements are never sent anywhere.