Body Fat Calculator (US Navy Method)

About Body Fat (US Navy)

The US Navy circumference method estimates body fat from tape measurements at the neck, waist, and hips (hips for women). It is field-friendly compared with DEXA or hydrostatic weighing.

Accuracy depends on consistent measuring technique and body shape. It is useful for tracking relative change over time rather than absolute lab-grade precision.

Results are fitness estimates, not medical diagnoses. Consult professionals for health assessments.

How to use this tool

Measure neck, waist, and hip (if required) per form instructions. Enter height and sex. Calculate to see estimated body fat percentage.

Formula & methodology

This body fat calculator (us navy method) applies the standard relationship below. Intermediate values are kept at full precision; only the displayed result is rounded.

US Navy body fat equations using log10 of circumference ratios; differ by sex

Tips for accurate results

• Measure at the same time of day, relaxed abdomen, tape parallel to floor.
• Do not pull the tape too tight—snug contact only.
• Track trend every 2–4 weeks rather than daily noise.
• Compare with performance and health markers, not aesthetics alone.

Frequently asked questions

Sources & references

The factors and formulas used by this tool follow these references:

• World Health Organization — A healthy lifestyle: WHO recommendations (BMI ranges)
• CDC — About Adult BMI
• Mifflin MD et al. (1990) — A new predictive equation for resting energy expenditure
• Jäger R et al. (2017) — ISSN Position Stand: protein and exercise
• ACOG — Methods for Estimating the Due Date

Health and fitness results are estimates for general education and planning. They are not medical advice and do not replace an assessment by a doctor, registered dietitian, or other qualified professional.

Last reviewed: September 2026. Found an error? Tell us and we will correct it.