Body Fat Percentage Calculator — US Navy Method, Free Online
Calculate your body fat percentage free using the US Navy method — enter your neck, waist and hip measurements for an accurate estimate. Results include your body fat category and ideal fat percentage range.
Last updated: June 2026
Your body fat
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- Fat mass
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- Lean mass
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Medical Disclaimer: This tool provides general health information for educational purposes only. Always consult a qualified healthcare professional for medical advice, diagnosis, or treatment.
About this tool
Measuring body fat at home
Body fat percentage tells you something your scale can't: how much of your weight is fat versus muscle, bone and water. Two people can weigh the same and have very different bodies, which is why body fat is a better guide to fitness than weight alone. This body fat calculator uses the US Navy circumference method, which estimates body fat from a few tape-measure readings — no calipers, scales or clinic visit required.
For men, the formula uses height, neck and waist; for women, it adds the hip measurement, since fat distribution differs by sex. Enter your measurements in metric or imperial units and the calculator returns your estimated body fat percentage, the category it falls into for your sex, and a breakdown of your fat mass and lean (fat-free) mass in your chosen weight unit.
Accurate measurement matters more than the formula. Measure your neck just below the larynx, your waist at its narrowest point, and your hips at their widest, keeping the tape level and snug without squeezing. Measure on bare skin, stand relaxed, and use the same spots each time — the trend across weeks is far more meaningful than any single reading. The US Navy method is a solid estimate for tracking progress, though it can differ by a few points from gold-standard methods like a DEXA scan.
Remember that some body fat is essential for health, hormone function and insulation, so the goal isn't the lowest possible number but a healthy range for your sex and goals. This tool is for general education, not medical assessment — consult a healthcare professional for advice. Everything is calculated privately in your browser. Measure up and enter your numbers above, then compare with the BMI and ideal weight tools.
How it works
Three quick steps — no account, nothing uploaded to a server.
Choose units and gender
Metric or imperial; the hip field shows for women.
Enter your measurements
Height, neck, waist (and hip), plus your weight.
See your composition
Body fat %, category, fat mass and lean mass.
General health information related to this tool is available from the US CDC healthy weight resources. Last checked July 2026.
FAQ
Frequently asked questions
How does the US Navy body fat method work?
The US Navy method estimates body fat from simple tape-measure circumferences rather than calipers or scales. For men it uses height, neck and waist; for women it adds the hip measurement. These are fed into a logarithmic formula that correlates well with more expensive methods, making it a practical at-home estimate.
Where do I measure my waist, neck and hip?
Measure your neck just below the larynx, your waist at the narrowest point (men often measure at the navel), and, for women, your hips at the widest point. Keep the tape snug but not compressing the skin, stand relaxed, and measure on bare skin for the most consistent result.
What is a healthy body fat percentage?
Healthy ranges differ by sex. For men, roughly 6–24% is typical, with athletes around 6–13% and fitness levels around 14–17%. For women, roughly 14–31% is typical, with athletes around 14–20% and fitness around 21–24%. Some fat is essential for health, so very low figures aren't the goal.
How accurate is this estimate?
The US Navy method is a good, repeatable estimate for tracking changes over time, but it's still an approximation — it can be a few points off compared with a DEXA scan or hydrostatic weighing. Measure consistently and focus on the trend rather than a single reading.
Is my data private?
Yes. Every measurement and the calculation stay in your browser — nothing is uploaded or stored. Your figures never leave your device.
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