How does the U.S. Navy tape method calculate body fat percentage?
The U.S. Navy circumference equations use logarithms of waist, neck, height, and—when applicable—hip measurements. Estimated fat mass = weight × body-fat percentage.
Health & fitness
Body fat percentage calculator
Estimate body-fat percentage, fat mass, and lean mass from height and circumference measurements.
- Metric and imperial units
- Instant updates as inputs change
- Data is calculated in this browser only
Results update as you type
Estimated body fat27.3 %
- Estimated fat mass
- 42 lb
- Estimated lean mass
- 112 lb
Circumference estimates are best used for trends. Re-measure at the same time, locations, and tape tension.
Calculation notes
Understand the Body fat percentage calculator
Uses the U.S. Navy circumference method with height, neck, waist, and female hip measurements. Tape placement and tension materially affect the estimate.
How should I take waist, neck, and hip measurements for body fat?
For consistent tracking, measure at the same locations, time of day, and tape tension. A small tape-position change can move the result by several percentage points.
Should I track one body-fat result or the measurement trend?
- Use repeated measurements to watch direction rather than relying on one reading.
- Lean mass is the remainder after estimated fat mass is subtracted from body weight.
How accurate is a circumference-based body fat calculator?
- Circumference equations are population estimates and can be less accurate for some body shapes.
- They do not replace DEXA or clinician-supervised assessment.
Content and calculation reviewed: