FFitCalc

Body Fat Calculator

Estimate body fat % with a tape measure.

Your details

cm
kg
cm

Measure below the larynx.

cm

At the navel, relaxed.

cm

Widest point. Women only.

Estimated body fat

16.4%

Fit

Fat mass

12.3kg

Lean mass

62.7kg

Category

Fit

Body fat category

Ess.AthleticFitAverageHigh

The U.S. Navy method estimates body fat from a handful of body circumferences. It's free, repeatable and surprisingly decent — typically within a few percent of a DEXA scan for most people. Body fat percentage tells you far more about your physique than scale weight alone.

Recommendations

  • Measure first thing in the morning, relaxed, using a snug (not tight) tape for consistency.
  • Track the trend over weeks rather than fixating on a single reading.

Watch out

  • This is an estimate. Body composition varies with hydration and measurement technique — expect a margin of ±3%.

Pro tips

  • Pair body-fat percentage with progress photos and strength numbers for the full picture.
  • Losing fat while keeping lean mass (recomposition) can leave scale weight flat — this metric reveals it.

Body fat percentage is a far better gauge of your physique and health than bodyweight or BMI. The U.S. Navy tape-measure method gives you a solid estimate with nothing but a tape measure.

Why body fat, not weight?

The scale can't tell muscle from fat. Two people at the same weight can look completely different. Tracking body-fat percentage reveals whether you're losing fat, gaining muscle, or both.

How the Navy method works

It uses log-based equations relating your height and key circumferences (neck, waist, and hips for women) to body density, then converts that to a fat percentage. Consistency in how you measure is the key to reliable tracking.

Frequently asked questions

It's one of the better field methods, usually within about 3% of a DEXA scan. Consistent measuring technique matters more than the exact number.

Roughly 10–20% for men and 18–28% for women is considered fit and healthy. Athletes often sit lower; essential fat is around 3–5% (men) and 10–13% (women).

Neck just below the larynx, waist at the navel, and — for women — hips at the widest point. Keep the tape level and snug, and measure while relaxed.

Sources

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