Army body fat calculator

Armies have moved away from body fat estimates. Check the US Army waist to height rule from July 2026 or the British Army entry table for BMI and waist, with the old tape estimate alongside.

Your details

US Army waist to height (AD 2026-13)

0.514

under 0.55: meets the standard

Waist to height ratio0.51 (0.5 to 0.59, NICE increased risk)
Largest waist under 0.55 for your height97.7 cm (38.5 in)
Room under the line6.4 cm (2.5 in)
BMI (not used by the US Army now)26.1
Old 2023 US tape estimate (no longer used)22.8% body fat

The US Army now uses only waist at the navel divided by height, measured at least twice a year, and 0.55 exactly does not pass. A reading of 0.55 or more is checked the same day by a different team before anything happens, and tape or body fat tests can no longer be used to appeal. NICE uses 0.5 as the healthy line for adults in the UK.

If your weight or eating is worrying you, your GP is a good place to start, and Beat (0808 801 0677) is there for eating worries.

The working

A man of 13 st, 5 ft 10 in, with a 36 inch waist

US Army: 36 ÷ 70 = 0.514, under 0.55, so it meets the standard. The largest waist under 0.55 at 5 ft 10 in is 0.55 × 177.8 cm, just under 97.8 cm (38.5 in), so there are about 6.4 cm to spare. 0.55 exactly does not pass.

British Army entry: 82.6 kg ÷ 1.778² = BMI 26.1, inside 18 to 29.9, so the waist is not needed and he could go straight to basic training if he passes the fitness test. At BMI 30 to 32 the waist must be 98 cm or less for men and 84 cm or less for women; at 32.1 to 33.5 a waist up to 101.9 cm (men) or 87.9 cm (women) can mean the development course first. Under 18s need BMI 17 to 29.9 with no waist adjustment.

The old 2023 US tape for men was −26.97 − 0.12 × weight in lb + 1.99 × abdomen in inches: −26.97 − 21.84 + 71.64 = 22.8%. We show it for reference only; the US Army no longer uses it.

What changed

From tape to waist to height

Army Directive 2026-13 (1 July 2026) made waist to height the only US Army body composition standard. Height and weight tables and the tape test were dropped, and a tape test cannot be used to challenge a result. Soldiers are measured at least twice a year, at least 7 days after a fitness test, and a reading of 0.55 or more is checked again the same day by a different team.

British Army

BMI first, then the waist

The British Army checks BMI and, for BMIs of 30 to 33.5, the waist, with the waist limits taken from NICE risk levels. The table here is from the Army recruitment policy (AGAI 40, April 2021) released under the Freedom of Information Act. The Army careers site now says BMI is usually 18 to 28, so treat this as a guide and check with a recruiter.

Measuring

Get it right

Tape level round the navel
Breathe out normally, do not suck in
Snug, not digging in
Take two readings, and a third if they differ by more than 1%

Read with care

What this cannot tell you

SelectionRecruiters and medical staff make the decision, not a calculator.
Muscular buildsBMI reads high on muscle, which is why the British Army looks at the waist.
HealthNeither number alone says whether someone is healthy.

Questions

Common questions

How does the US Army measure body fat now?

It no longer does. Since July 2026 the US Army uses waist at the navel divided by height, and soldiers need to be under 0.55. From 2023 to 2026 it used a one site tape.

What BMI do you need for the British Army?

Usually 18 to 29.9 to go straight to basic training. From 30 to 32 your waist is measured (98 cm or less for men, 84 cm or less for women), and some people with BMI up to 33.5 do a development course first. Under 18s need 17 to 29.9. Check current figures with a recruiter.

Is the tape test accurate?

It is a fair estimate for groups and less precise for one person, which is one reason the US Army moved to waist to height.

Is 0.55 a healthy waist to height ratio?

NICE uses under 0.5 as the healthy range for adults and 0.6 or more as high risk. The Army line of 0.55 sits in the middle.

Sources

Last checked 21 October 2026. Spotted something wrong? Tell us and we will fix it.

Before you push on

New to exercise, or got a heart, lung or joint condition? Have a word with your GP or practice nurse first. Stop and get help if you feel chest pain, faintness or unusual breathlessness, and call 999 if it is severe.