$60 off your first month$60 offyour first month
Pallas
All calculators

Body fat · US Navy method

How much of your weight is actually fat?

A tape measure tells you something the scale can't: how much of your weight is fat versus muscle. Enter a few measurements to estimate your body-fat percentage — the muscle-vs-fat picture BMI leaves out.

Estimate your body fat

Measure with a snug, level tape: neck just below the larynx, waist at the navel, and (for women) hips at the widest point. Weight is optional — add it to see your fat-mass and lean-mass split.

Why body fat tells you more than BMI

BMI uses only your height and weight, so it can't separate muscle from fat — two people with the same BMI can have very different bodies. Body-fat percentage measures composition directly, which is what actually drives metabolic risk and what you're really trying to change. If you've already run your BMI, this fills in the half of the picture it leaves out.

Measuring accurately

  • Use a flexible tape, snug to the skin but not compressing it, on bare skin.
  • Neck: just below the larynx, sloping slightly downward to the front.
  • Waist: at the navel for men; at the narrowest point for women.
  • Hips (women): around the widest part of the buttocks.
  • Measure two or three times and average — small tape errors move the estimate a lot.

Holding onto lean mass while you lose

When you lose weight, the goal is to drop fat while keeping muscle. Tracking body-fat percentage alongside the scale tells you whether you're succeeding. Adequate protein and resistance training are the most evidence-supported levers for protecting lean mass during a calorie deficit — set your daily number with the protein calculator, and see what a year of treatment can look like with the projection calculator.

Common body fat questions

It's a circumference-based formula developed by the Naval Health Research Center that estimates body-fat percentage from your height and a few tape measurements — neck and waist for men, plus hips for women. It's the most widely used at-home method because it needs nothing but a tape measure, and it tracks reasonably close to lab methods for most people.

For most adults the US Navy method lands within about 3–4% of a DEXA scan — accurate enough to track change over time and spot your general category. It's least accurate at the extremes (very lean or very high body fat) and for people with unusual proportions. For a precise clinical number, a DEXA scan or BodPod is the gold standard.

Use a flexible tape held snug but not compressing the skin, and measure on bare skin. Neck: just below the larynx (Adam's apple), sloping slightly down to the front. Waist: at the navel for men; at the narrowest point for women. Hips (women): around the widest part of the buttocks. Take each measurement two or three times and average them — small errors move the estimate a lot.

The American Council on Exercise ranges are: men — essential 2–5%, athletic 6–13%, fitness 14–17%, average 18–24%, above average 25%+. Women carry more essential fat: essential 10–13%, athletic 14–20%, fitness 21–24%, average 25–31%, above average 32%+. 'Healthy' spans a wide band; trend matters more than a single number.

BMI only uses height and weight, so it can't tell muscle from fat — a muscular person and a higher-fat person can share the same BMI. Body-fat percentage measures the thing that actually drives metabolic risk, and the fat-mass vs lean-mass split shows whether weight changes are coming from fat or muscle.

The goal of weight loss is to drop fat while keeping muscle. Tracking body-fat percentage (alongside the scale) tells you whether you're succeeding. Adequate protein and resistance training are the most evidence-supported ways to protect lean mass during a calorie deficit — use the protein calculator to set your daily target.

Other calculators