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Body Fat Calculator: US Navy Tape Method and Waist Risk Check

Free · No sign-up · Updated October 2026
Estimate body fat with the US Navy tape method (neck, waist, hip, height) and check your waist against HPB's Asian cut-offs: 90 cm men, 80 cm women.
Sex
cm
cm

Just below the Adam's apple

cm

Around the navel

cm

Widest part (for waist-to-hip only)

kg

Adds fat mass and lean mass in kg

16.7%
  • Essential fat 2 to 5%
  • Athletes 6 to 13%
  • Fitness 14 to 17%
  • Average 18 to 24%
  • Obese 25%+

Waist risk check

For this check HPB measures halfway between your lowest rib and the top of your hip bone, after breathing out.

  • Waist size

    84 cm

    Within HPB's 90 cm cut-off for Asian men.

  • Waist-to-height

    0.49

    Healthy on the NICE scale (0.4 to 0.49).

  • Waist-to-hip

    0.88

    Within HealthHub's 0.9 limit.

A tape-measure estimate, usually within 3 to 4 percentage points of a lab test. It reads high for very muscular people and is not meant for pregnancy or under-18s.

Estimated body fat

16.7%

Fitness (ACE category)
Waist vs HPB cut-off
84 cm is within 90 cm
Waist-to-height ratio
0.49 (healthy)
Waist-to-hip ratio
0.88 (within 0.9)

How this works

Body fat is estimated with the circumference equations Hodgdon and Beckett developed at the US Naval Health Research Center in 1984, the basis of the US military tape test. With measurements in inches: for men, body fat % = 86.010 × log10(waist − neck) − 70.041 × log10(height) + 36.76; for women, body fat % = 163.205 × log10(waist + hip − neck) − 97.684 × log10(height) − 78.387. Your centimetres are converted to inches first. The equations were fitted against underwater weighing and have a standard error of about 3 to 4 percentage points, so treat the result as an estimate within a few points.

Measure with a soft tape against bare skin, without pulling it tight. Neck: just below the Adam's apple. Waist for the body fat formula: around the navel for men, at the narrowest point for women. Hip (women): around the widest part of the buttocks. The body fat bands are the American Council on Exercise (ACE) categories: for women, 10 to 13% is essential fat, 14 to 20% athletes, 21 to 24% fitness, 25 to 31% average and 32% or more obese; for men, 2 to 5%, 6 to 13%, 14 to 17%, 18 to 24% and 25% or more.

The waist risk check uses the Health Promotion Board's cut-offs for Asians: a waist above 90 cm for men or above 80 cm for women implies abdominal obesity, which raises the risk of diabetes, high blood pressure and heart disease. HPB measures the waist halfway between the lowest rib and the top of the hip bone, after breathing out. HealthHub also flags a waist-to-hip ratio above 0.9 for men or 0.85 for women. Waist-to-height ratio uses the UK NICE bands: 0.4 to 0.49 healthy, 0.5 to 0.59 increased and 0.6 or more high central fat, so keep your waist under half your height.

FAQs

What is a healthy waist size in Singapore?

90 cm or less for men and 80 cm or less for women. The Health Promotion Board says a waist above 90 cm (35.5 inches) for Asian men or above 80 cm (31.5 inches) for Asian women implies abdominal obesity and higher risk of diabetes and heart disease.

How accurate is the US Navy body fat method?

Within about 3 to 4 percentage points for most adults. The equations were fitted against underwater weighing with a standard error of about 3 to 4 points; results drift for very muscular or very lean people, and a sloppy tape measurement moves the answer by a point or more.

What is a good body fat percentage?

On the ACE scale, 14 to 17% is the fitness range for men and 21 to 24% for women, and 18 to 24% (men) or 25 to 31% (women) is average. ACE classes 25% or more for men and 32% or more for women as obese.

What is a healthy waist-to-height ratio?

Under 0.5, meaning your waist is less than half your height. At 170 cm, that is a waist under 85 cm. UK NICE guidance classes 0.5 to 0.59 as increased and 0.6 or more as high central fat, for adults of all ethnicities.

Sources