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Body Fat Calculator

Estimate your body fat percentage from tape measurements — the US Navy method.

Free · No sign-up · Works on your phone between sets · Updated

Sex
Units

Estimated body fat

16.1%

US Navy tape method — typically within 3–4 points of a DEXA scan. Trends across weeks matter more than any single reading.

Calculate your FFMI

How to measure#

Keep the tape snug but not compressing the skin, measure twice, and always at the same time of day — morning before food is the most repeatable.

Methodology#

The formulas come from the US Naval Health Research Center. For men: 495 ÷ (1.0324 − 0.19077 × log₁₀(waist − neck) + 0.15456 × log₁₀(height)) − 450, in centimeters. Women use waist + hips − neck with separate coefficients. Circumference methods estimate fat distribution from where you store it, which is why they track trends well even if any single reading is a few points off.

Reference ranges#

CategoryMenWomen
Essential fat2–5%10–13%
Athletes6–13%14–20%
Fit14–17%21–24%
Average18–24%25–31%
Above average25%+32%+

Know your body fat? Feed it into the FFMI calculator to see how much muscle you carry for your height, or the TDEE calculator to plan your nutrition.

Body composition changes come from consistent training. Gript makes logging effortless and shows your strength trending in clean charts.

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Thanks for adding the way to log measurements in the app, that was the last thing that I was missing.
Emil S. · App Store

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Frequently asked questions#

How does the Navy body fat method work?

It estimates body fat from circumference measurements — neck and waist for men, plus hips for women — combined with height, using formulas developed by the US Naval Health Research Center. All you need is a tape measure.

How accurate is the tape method?

Usually within 3–4 percentage points of a DEXA scan — accurate enough to track trends over time, which is what matters. Measure at the same time of day, relaxed, and take each measurement twice for consistency.

What is a healthy body fat percentage?

For men, roughly 10–20% is a fit-to-healthy range, with athletes often at 6–13%. For women, roughly 18–28% is fit-to-healthy, with athletes at 14–20%. Essential fat is about 3% for men and 12% for women — going below that is dangerous.

Where exactly do I measure?

Neck: just below the larynx, tape sloping slightly down at the front. Waist: for men at the navel, for women at the narrowest point. Hips (women): at the widest point. Keep the tape snug but not compressing the skin.

Sources

The formulas and ranges on this page come from the following peer-reviewed research.

  1. Prediction of percent body fat for U.S. Navy men from body circumferences and height (Report 84-11)Hodgdon JA, Beckett MB. Naval Health Research Center, 1984.
  2. Prediction of percent body fat for U.S. Navy women from body circumferences and height (Report 84-29)Hodgdon JA, Beckett MB. Naval Health Research Center, 1984.
  3. Body composition in the military services: standards and methodsNational Research Council, Committee on Military Nutrition Research. National Academies Press, 1992.

More free tools

FFMI Calculator

Your fat-free mass index — how much muscle you carry for your height.

TDEE Calculator

The calories you burn per day, from the most validated BMR equation plus your activity level.

Calorie Deficit Calculator

Your daily calorie target and a realistic timeline to reach your goal weight.

In the Gript Help Center