Bemivo
Body fat calculator
Your body fat percentage from a tape measure, with your lean mass and fat mass. The US Navy method, the one the military used for decades.
Waist at the navel, neck below the larynx, hip at its widest.
Only for lean and fat mass: the percentage comes from the tape measurements.
A screening number, not a diagnosis. Talk to a doctor about anything that worries you.
About this number
The Navy method estimates fat from circumferences, so it tracks change well and reads high on wide waists with low muscle.
The equations come from a 1984 US Navy study that checked tape measurements against underwater weighing, and the US military screened body fat with them for decades. The categories are the American Council on Exercise's, with different ranges for men and women because women carry more essential fat.
%= 495÷ (1.0324− 0.19077× log(Waist−Neck)+ 0.15456× log(Height))− 450
log is the base-10 logarithm. The formula works in centimetres, so inches are converted first.
Sources
- Body composition in the military services: standards and methods
National Academies Press, 1992
- Anthropometric Measurements: When to Use this Assessment
American Council on Exercise, 2014
Questions people ask
Where do I measure my neck and waist for the Navy method?
The neck just below the larynx (the Adam's apple), the waist at the navel, and for women the hip at its widest. Keep the tape level and snug without pressing in, and measure at the same time of day each time.
How accurate is the Navy method?
It is an estimate. As a single number it can be a few points off a lab measurement, but because the error stays much the same for the same person, it is good for seeing whether your body fat is going up or down.
What body fat percentage is obese?
In the American Council on Exercise categories this calculator uses, 25 percent or more for men and 32 percent or more for women. The line is higher for women because they carry more essential fat.
What is a normal body fat percentage by age?
The American Council on Exercise categories used here do not change with age. For women, 21 to 24 percent is the fitness range and 25 to 31 average; for men, 14 to 17 and 18 to 24.
Every calculator, free
Eight ways to read the same measurements. No account, nothing saved anywhere but your browser.
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- Child BMI calculatorPercentile for age and sex, children and teens 2 to 19
- Kg to lbs to stone, and cm to feet and inchesKilograms, pounds, stones, centimetres, feet and inches
Bemivo for iPhone and Android
Keep every number, and see where it is going.
The Bemivo app is a weight tracker: a trend line that ignores the daily noise of the scale, goals with a projected date, and the whole family in one account. It starts with a free trial.
- History and a trend line that ignores daily noise
- Goals with a projected date
- Home Screen widgets, and Lock Screen on iPhone
- Weigh-in reminders
- Up to 10 profiles for the family
- Body measurements, CSV and a PDF for your doctor
The calculators on this website stay free.