Body Fat Calculator
Estimate body fat percentage using the tape-measure circumference method. Measurements should be taken with a tape measure while relaxed.
| Gender | |
| Units | |
| Height | cm |
| Neck | cm |
| Waist | cm |
| Weight (optional) |
How to measure: Neck — below the larynx, sloping slightly down. Waist (men) — at the navel; (women) — at the narrowest point. Hip (women) — at the widest point.
Result
Your estimate will appear here.
About the circumference method
This method estimates body fat from body circumferences and height. It is convenient but only an estimate; results can vary with measurement technique and body type. Other methods (DEXA, calipers, hydrostatic weighing) may be more accurate.
How it works
Body fat percentage is estimated from body measurements using the circumference method (a circumference-based estimate).
Formula (circumference method, simplified)
- Uses height and circumferences (e.g. waist/neck, and hip for women) with logarithmic formulas to estimate body fat %. Tape placement and measurement consistency matter.
Assumptions
- An estimate, not a medical body-composition scan. Accuracy varies by body shape and measurement technique.
General information only, not medical advice.
How to use the Body Fat Calculator
It takes a few seconds, and every figure is calculated in your browser.
- Select your gender.
- Choose the units.
- Enter your height.
- Enter your neck measurement.
- Enter your waist measurement.
- Enter your hip measurement.
- Press Calculate — the result appears in the dark panel beside the form.
- Use Copy, CSV, Share or Print under the result if you want to keep it.
Body Fat Calculator — frequently asked questions
What formula does the Body Fat Calculator use?
This method estimates body fat from body circumferences and height. It is convenient but only an estimate; results can vary with measurement technique and body type. Other methods (DEXA, calipers, hydrostatic weighing) may be more accurate.
How does the Body Fat Calculator work?
Body fat percentage is estimated from body measurements using the circumference method (a circumference-based estimate).
What assumptions and limitations should I know about?
An estimate, not a medical body-composition scan. Accuracy varies by body shape and measurement technique.
Last updated 10 November 2026 · Formula, worked example and assumptions are documented above, and every result is calculated in your browser.