Body Fat Percentage Calculator

Written byOleh Soloninupdated 27 September 2026

Sex

Height cm

Neck cm

Waist cm

Hip cm

Result

Body Fat Percent18.3%
CategoryAverage

This result is informational only and is not professional advice.

Circumference measurements instead of a single ratio

Estimate body fat percentage from neck, waist and hip measurements. More informative than BMI, and still only an estimate.

The Navy method uses circumferences rather than weight, which lets it distinguish between a heavy, muscular build and one carrying more fat — something BMI structurally cannot do.

It is an estimate from circumferences, not a measurement of body composition, and the calculator cannot know how far off a particular result is. Measurement technique matters enormously: pull the tape too tight and you will 'lose' several percent without changing anything.

How to use

Choose your sex and enter your height in centimetres.
Measure the neck just below the larynx, and the waist — at the navel for men, at the narrowest point for women.
Women also need the hips, around the widest part of the buttocks.
Keep the tape snug but not tight, and measure at the same points once a month to see the trend.

How the waist moves the estimate

The waist is the formula's main variable. For a man of 176 cm with a 39 cm neck, every 4 cm of waist adds about three percentage points: from 8.2 percent at 76 cm to 26.5 percent at 100 cm.

Hence the sensitivity to technique: two centimetres of tape tension is a point and a half.

A man, height 176 cm, neck 39 cm. Every row comes from the calculator on this page.
Waist, cm	Body fat, %	ACE category
76	8.2	athletes
80	11.8	athletes
84	15.2	fitness
88	18.3	average
92	21.2	average
96	23.9	average
100	26.5	obese

Women are read on a different scale

Women carry more essential fat — 10 to 13 percent against 2 to 5 for men — so ACE sets the bands higher: fitness 21–24 percent, average 25–31, obese from 32. For men the same bands are 14–17, 18–24 and from 25.

A woman at 24.9 percent is in the fitness band, where the men's scale would call the same figure average.

A woman, height 165 cm, neck 33 cm, hips 98 cm. Every row comes from the calculator on this page.
Waist, cm	Body fat, %	ACE category
64	22.8	fitness
68	24.9	fitness
72	26.9	average
76	28.9	average
80	30.9	average
86	33.8	obese

What this calculator shows

An estimate of body fat percentage by the US Navy formula
The category on the American Council on Exercise (ACE) scale — a separate one for men and women

What to keep in mind

Requires neck and waist for men, plus hips for women.
Measure relaxed, at the same point each time, with the tape snug but not compressing the skin.

Where the numbers come from

Checked against the US Navy circumference method.

FAQs

What is a healthy body fat percentage?

On the ACE scale men are in the fitness band at 14–17 percent, average at 18–24 and obese from 25. For women the same bands are 21–24, 25–31 and from 32. Essential fat on the ACE scale is 2–5 percent for men and 10–13 for women; those are not weight-loss targets, and going there is a health risk.

How accurate is the Navy method?

It is an estimate from tape measurements, and the individual error depends on the person, the technique and the reference method; no fixed limit is established here. Technique matters a lot: a tape pulled two centimetres tighter takes a point and a half off.

How does this compare to smart scales?

Bioimpedance scales depend on how hydrated you are and can swing several percent between morning and evening. Tape measurements are more stable if your technique is consistent.

Why do women need a hip measurement?

Fat distribution differs, and the equation was fitted separately for each sex to account for that.

Where exactly do I measure the waist?

In the Navy method men measure at the navel and women at the narrowest point. Above all, use the same point every time, after breathing out, without pulling the stomach in.

Is the number itself worth chasing?

Not really. Given the error margin, direction matters more — the same tape, the same spots, once a month.

Worked example

Consistency beats precision

Input: a man, height 176 cm, neck 39 cm, waist 88 cm, hips 98 cm

Output: 18.3%

Note: That is ACE's 'average' band. The same body measured at 86 cm — the tape pulled two centimetres tighter — gives 16.8 percent: a point and a half without any change in the body. The trend is the useful signal, not a single reading.

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Result

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