Body Fat Percentage Calculator
Estimate your body fat percentage using simple tape-measure measurements, based on the widely used US Navy method.
About this body fat percentage calculator
Unlike BMI, which only considers weight and height, body fat percentage attempts to estimate actual fat mass using body circumference measurements, giving a different kind of insight into body composition.
How body fat percentage calculator works
This uses the US Navy circumference method, which calculates body fat from waist, neck, and height (plus hip measurement for women), based on logarithmic relationships between these measurements validated against more precise body-fat testing methods.
Common uses
- Tracking body composition changes over time alongside weight
- Getting a body fat estimate without specialized equipment
- Comparing against general fitness body fat ranges
How to use this tool
- Select your sex.
- Measure and enter your waist, neck, and height.
- Enter your hip measurement too, if you selected female.
- See your estimated body fat percentage instantly.
What to know before using it
This is an estimate based on body measurements, not a lab-grade body composition scan (like DEXA). Accuracy depends on measuring correctly and consistently. It is a general fitness indicator, not a medical diagnosis.
Privacy and browser-first processing
This tool runs entirely in your browser using JavaScript. Nothing you enter is uploaded or stored.
Frequently asked questions
How accurate is the US Navy method?
It is one of the more reasonably accurate measurement-based methods available without special equipment, though it is still an estimate, not a precise lab measurement like a DEXA scan.
Where exactly should I measure my waist and neck?
Measure your neck just below the larynx, and your waist at its narrowest point (or at the navel, depending on the specific protocol you follow), consistent measurement technique matters for accuracy.