Body Fat Calculator

The US Navy method estimates body fat percentage from a handful of body circumference measurements, without special equipment beyond a flexible tape measure. It was developed as a practical field alternative to more precise but less accessible methods like DEXA scanning or hydrostatic weighing.

The formula

All measurements are in centimeters. Men need waist, neck, and height; women additionally need hip circumference.

How to measure accurately

• Neck: measure just below the larynx (Adam's apple), tape sloping slightly downward toward the front.
• Waist: measure at the narrowest point, typically at the navel for men and the narrowest point for women.
• Hip (women): measure at the widest point around the buttocks.

Accuracy and limitations

The US Navy method is reasonably accurate for most body types compared to gold-standard methods like DEXA scanning, typically within a few percentage points, but it can be less accurate for people with atypical body fat distribution or very high or low body fat levels. Measurement technique also matters significantly — inconsistent tape placement or tension can shift the result noticeably.

Common mistakes

• Measuring over clothing. Always measure directly against skin for accuracy.
• Pulling the tape too tight or too loose. The tape should sit snugly without compressing the skin.
• Taking a single measurement. Measuring at the same time of day, a few times, and averaging improves consistency.

This tool provides a general estimate for informational purposes and is not a substitute for a clinical body composition assessment.

Frequently asked questions