Body Fat Calculator
Estimate body fat percentage from body measurements using the US Navy method.
28.9%
About this calculator
What Is Body Fat Percentage?
Body fat percentage is the share of your total weight that is fat tissue. Unlike weight or BMI, it separates fat from everything else — muscle, bone, organs and water — so it says more about your actual body composition. This body fat calculator estimates your percentage from tape measurements (neck, waist and, for women, hips) along with height, using a tape-measure method originally developed by the U.S. Navy. For the most consistent results, measure to the nearest half centimeter and always measure at the same points.
Essential Fat vs. Storage Fat
Not all body fat is a problem. Essential fat is the minimum your body needs for normal function — protecting organs, regulating hormones and supporting reproduction — and it is higher in women (about 10%–13%) than in men (about 2%–5%). Storage fat is the energy reserve beneath the skin and around organs. Too little of either is unhealthy, and so is too much.
Worked Example
A woman with height 165 cm, neck 34 cm, waist 80 cm, and hip 95 cm comes out to about 28.9% body fat — in the "Average" range. A man with height 178 cm, neck 38 cm, and waist 90 cm comes out to about 20.1% — also "Average," using the ranges for men.
Typical Body Fat Ranges
- Essential fat: 10%–13% women, 2%–5% men.
- Athletes: about 14%–20% women, 6%–13% men.
- Fitness: about 21%–24% women, 14%–17% men.
- Average: about 25%–31% women, 18%–24% men.
- Obese: above about 32% in women and 25% in men.
Ideal percentages also rise with age, so a healthy number at 25 is lower than a healthy number at 55.
Why Body Fat Can Say More Than BMI
Two people with the same height and weight can have very different body fat. A muscular person may land in the "overweight" BMI band while carrying little fat, and an inactive person at a "normal" BMI may carry a lot. Where fat sits matters too: fat stored around the waist is linked with greater health risk than fat on the hips and thighs. Compare with your BMI and your ideal weight range for the full picture.
Accuracy and Limits
Tape-measure formulas are estimates and can be off by a few percentage points. More precise methods — DEXA scans, hydrostatic weighing and calipers — exist but need equipment or a clinic. Treat a calculator result as a way to track change over time rather than as an exact diagnosis, and talk to a healthcare professional before making major diet or training changes.
Worked example
At 165cm tall with a 34cm neck, 80cm waist, and 95cm hip, the US Navy formula estimates about 29% body fat — in the "Average" category for women.
Frequently asked questions
How accurate is the US Navy method?
It's a widely used estimate, typically within a few percentage points of more precise methods like DEXA scans, and far more accessible — all it needs is a measuring tape.
Why does the formula need different measurements for men and women?
Men and women tend to store fat differently (waist for men, waist and hip for women on average), so the Navy method uses a different set of measurements and constants for each to stay accurate.
Where exactly should I measure my waist and neck?
Waist: at the narrowest point, usually just above the navel. Neck: just below the larynx (Adam's apple), sloping slightly downward at the front. Keep the tape snug but not compressing the skin.
What do the body fat categories mean?
They're standard ACE ranges — essential fat is the minimum needed for basic health, athletes and fitness ranges reflect regular training, and average/obese reflect typical and elevated ranges respectively. They're general guidelines, not a diagnosis.
