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Body Fat Calculator

Estimate your body fat percentage with a tape measure, using the same circumference method the US Navy uses.

Quick answer

The US Navy method estimates body fat from height, neck and waist (plus hips for women), usually within a few points of a DEXA scan. 14–24% is a typical fitness-to-average range for men, 21–31% for women. Compare with your BMI.

  • Free
  • No sign-up
  • Fitness
  • Updated October 2026

Used by the formulas; they were derived from male and female study groups.

ft
in
in

Just below the larynx.

in

Men: at the navel. Women: at the narrowest point.

lb

Adds fat mass and lean mass.

Body fat

16.5%

Fitness

Category (ACE ranges)
Fitness
Fat mass
28 lb
Lean mass
142 lb
Show the working
  1. US Navy method, measurements in cm: height 177.8, waist − neck = 47
  2. Body fat = 16.5%

About the Body Fat calculator

The US Navy method estimates body fat from a few circumference measurements and your height. It is typically within a few percentage points of lab methods for most people, which makes it a useful way to track change over time without special equipment.

Measure on bare skin, relaxed, at the same time of day each time. Small errors in the waist measurement move the result noticeably, so take each measurement twice and use the average.

How to use it

  1. Choose units and sex.
  2. Enter height, neck and waist (and hips for women).
  3. Optionally add weight to see fat mass and lean mass.
  4. Re-measure every 2–4 weeks to track progress.

The formula

Men: 495 ÷ (1.0324 − 0.19077·log10(waist − neck) + 0.15456·log10(height)) − 450

  • Women: 495 ÷ (1.29579 − 0.35004·log10(waist + hip − neck) + 0.22100·log10(height)) − 450.
  • All measurements in centimetres.

Worked example

Man, 178 cm, neck 38 cm, waist 86 cm

  1. waist − neck = 48 cm.
  2. log10(48) = 1.681; log10(178) = 2.250.
  3. 495 ÷ (1.0324 − 0.3207 + 0.3478) − 450 = 17.2% body fat.

Frequently asked questions

How accurate is the Navy method?

It usually lands within about 3–4 percentage points of DEXA scans, and is more consistent when the same person takes the measurements the same way.

What is a healthy body fat percentage?

The American Council on Exercise lists 14–24% as fitness-to-average for men and 21–31% for women. Essential fat is about 2–5% for men and 10–13% for women.

Where exactly do I measure my waist?

Men measure horizontally at the navel; women at the narrowest point of the waist. Don’t pull the tape tight or hold your breath.

Results are estimates for healthy adults, not medical advice. Talk to a doctor or registered dietitian before major changes to diet or training, especially if you are pregnant or have a health condition.

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