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Body fat percentage gives a more direct picture of body composition than BMI alone, but precise methods like DEXA scans or skinfold calipers require special equipment. The US Navy circumference method estimates body fat using just a tape measure — less precise, but accessible to anyone.
This calculator uses the US Navy method's standard formula, based on your height, neck, waist, and (for women) hip measurements.
How it works
Enter your sex, height, neck circumference, and waist circumference. Women also enter hip circumference, which the formula requires but men's calculation doesn't use. The tool applies the US Navy method's standard logarithmic formula to estimate body fat percentage.
- Enter sex.
- Enter height (cm).
- Enter neck circumference (cm).
- Enter waist circumference (cm).
- Enter hip circumference (cm).
- Click Calculate to see your results.
Examples
Estimating body fat for a male
A 175cm male with a 38cm neck and 85cm waist gets an estimated body fat percentage from the formula's waist-to-neck ratio.
Who should use it
- Estimating body fat percentage without access to specialized equipment.
- Tracking body composition changes over time during a fitness program.
Industry applications
- Fitness and personal training
- Military and physical fitness assessment
Advantages
- Requires only a tape measure — no special equipment.
- Well-established, standard formula with decades of use.
Limitations
- Less precise than skinfold calipers, DEXA, or hydrostatic weighing.
- Sensitive to measurement technique consistency.
Common mistakes to avoid
- Measuring inconsistently between sessions (different location or tightness), making tracked changes unreliable.
- Expecting DEXA-scan precision from a tape-measure-based method.
Best practices
- Measure at the same time of day and body position each time for consistent tracking.
- Use this as a trend-tracking tool over time rather than a one-off precise measurement.
Tips
- Track the trend over weeks or months rather than reacting to any single measurement, since small measurement inconsistencies can shift the result noticeably.