Body Fat Calculator
Estimate your body fat percentage with nothing but a tape measure, using the U.S. Navy method: height, neck and waist, plus hips for women. Add your weight to see your fat and lean mass. The math runs in your browser: nothing you type is sent anywhere.
Your estimated body fat
Fill in the form and press Calculate to see your estimated body fat percentage and, with your weight, your fat and lean mass.
- Estimated body fat
- Fat mass
- Lean (fat-free) mass
These are estimates, not medical or dietary advice. How we estimate, with sources
How to measure at home
Use a flexible tape, snug but not pressing into the skin, and measure in the morning before eating. Neck: just below the larynx (Adam's apple), with the tape sloping slightly down to the front. Waist: men at the navel, women at the narrowest point; stand relaxed and don't pull your stomach in. Hips (women): at the widest point of the buttocks. Measure twice and use the average.
How accurate is this?
The Navy equations estimate body fat from circumferences and height. They were built on large groups, so for any one person they can be off by several percentage points, especially at very low or very high body fat. Calipers, smart scales and DEXA scans each have their own error too. Whatever you use, use the same method, the same way, every time: the trend is more useful than any single number.
Body fat ranges for men and women
The American Council on Exercise groups body fat into these ranges. They describe groups of people, not a target for you, and an estimate from a tape measure can land in the next band over.
Body fat categories (American Council on Exercise)
| Category | Women | Men |
|---|---|---|
| Essential fat | 10–13% | 2–5% |
| Athletes | 14–20% | 6–13% |
| Fitness | 21–24% | 14–17% |
| Average | 25–31% | 18–24% |
| Obese | 32%+ | 25%+ |
Using your body fat % for your targets
Your lean mass is your weight minus your fat mass. It feeds two other tools: the FFMI calculator, which divides it by your height squared, and protein estimates, since muscle is what you're trying to keep. Re-measure every few weeks during a cut: if your weight drops and your lean mass holds, the weight you're losing is mostly fat.
Track the trend, not one measurement
A single tape reading moves with water, food and how you hold the tape. The BodyMacros app keeps your weight trend and your lifts in one place and re-estimates your calorie and macro targets each week, so you can see whether you're losing fat and keeping muscle.
FAQ
How do I calculate body fat percentage at home?
With a tape measure and the U.S. Navy method: measure your height, your neck below the larynx and your waist (at the navel for men, the narrowest point for women), plus your hips if you're a woman. This calculator turns those into an estimate. Measure the same way each time and compare the trend over weeks.
What is the most accurate body fat calculator?
No formula is accurate for everyone. Tape and caliper equations can be off by several percentage points for one person; lab methods such as DEXA are closer but cost more and have their own error. For tracking, consistency matters most: use one method, the same way, and follow the trend rather than any single result.
Navy vs Army body fat calculator: what's different?
Both estimate body fat from tape measurements, but they use different equations and the Army has changed its own method over the years. This calculator uses only the U.S. Navy equations by Hodgdon and Beckett (1984), shown on our sources page, so its results won't always match an Army calculator for the same measurements.
What is a healthy body fat percentage for men and women?
The American Council on Exercise puts average body fat at 18–24% for men and 25–31% for women, fitness ranges at 14–17% and 21–24%, and essential fat at 2–5% and 10–13%. These describe groups, not a personal target. If you're unsure what's right for you, ask a doctor or a registered dietitian.
Track this in the app
Log your food and your lifts in one place. Your estimates adjust each week to how you eat and train.
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