Body Fat Calculator
Estimate your body fat percentage using the trusted US Navy circumference method from your height, neck, waist (and hip) measurements. Free, private, instant.
Last reviewed by the Radiatus Cloud team
Need this done properly for your business?
Radiatus delivers secure cloud, DevOps & compliance engineering.
Estimate body fat from tape measurements
Body fat percentage is more informative than weight alone, but measuring it precisely needs specialist equipment. The US Navy circumference method estimates it from simple tape measurements instead. This calculator applies that method to your height and circumference measurements to estimate your body fat percentage.
Why circumferences work
The method exploits the fact that fat and lean tissue distribute in predictable ways, so measurements at the neck, waist and (for women) hips, combined with height, correlate with overall body fat well enough for a useful estimate. It is far more accessible than underwater weighing or a body scan, which is exactly why the Navy adopted it, and it is reasonably consistent when you measure carefully at the same points each time.
An estimate that rewards careful measurement
These are estimates from a standard formula for general information, not medical advice. Individual health depends on far more than any single number, so treat the result as a rough guide and consult a professional for anything that matters. The calculation runs entirely in your browser, so your figures are not uploaded.
Related tools
- Percentage Calculator — Calculate percentages, percentage change, increase and decrease, and reverse percentages, with the working shown for each result.
- Statistical Calculator — Calculate mean, median, mode, standard deviation, and more.
- Probability Calculator — Calculate probabilities for single and combined events, including conditional probability and Bayes' theorem.
- Scientific Calculator — Perform advanced mathematical operations including trig, log, and exponents.
Frequently Asked Questions
How does the US Navy method work?
It estimates body fat from tape measurements, neck and waist, plus hips for women, combined with height, using a formula that correlates those circumferences with overall body fat.
Why use circumferences instead of a scan?
Because a tape measure is accessible to anyone, while precise methods like underwater weighing or a body scan need specialist equipment. The Navy method trades a little accuracy for practicality.
How accurate is it?
It is a reasonable estimate when you measure carefully at consistent points. It is less precise than a laboratory method but far more accessible, and consistency matters more than a single reading.
Does it differ for men and women?
Yes. The measurements differ, with hip circumference included for women, reflecting how fat distribution differs.
Is this medical advice?
No. It is a general estimate. Consult a professional for an accurate assessment.
Privacy & Security
All processing happens locally in your browser — nothing is uploaded.
How to Use
Choose sex and enter your measurements in cm. Body fat % and category are calculated instantly.
Disclaimer: This tool is provided "as is" without warranty of any kind. Results are for educational and utility purposes.
Related Tools
Percentage Calculator
MathCalculate percentages, percentage change, increase and decrease, and reverse percentages, with the working shown for each result.
Statistical Calculator
MathCalculate mean, median, mode, standard deviation, and more.
Probability Calculator
MathCalculate probabilities for single and combined events, including conditional probability and Bayes' theorem.