Which method does this calculator use?

The US Navy circumference method with sex-specific equations using waist, neck, hips (for women), and height.

How accurate is the Navy method?

It is a practical field estimate. It can differ from lab methods like DEXA or hydrostatic weighing, but is useful for tracking trends when measurements are taken consistently.

Why is my body fat different from a smart scale?

Smart scales use bioelectrical impedance analysis (BIA), which is sensitive to hydration and device algorithms. Different methods can yield different results.

How often should I measure body fat?

Every 2–4 weeks during a program, taking measurements at a similar time of day with consistent tape placement.

What ranges are typical?

Typical ranges differ by sex and age. Emphasize trend over time, along with waist and hip measurements and performance metrics, rather than a single value.

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About Body Fat Percentage (US Navy) Calculator

This calculator estimates your body fat percentage using the US Navy circumference method. It uses waist and neck (plus hips for women) together with height, in cm or in. Results help track body composition trends better than BMI alone.

How to measure

Height: Stand tall, no shoes. Enter in cm, in, or ft+in.
Neck: Below the larynx (Adam’s apple), tape slightly angled down front.
Waist: Horizontal at the narrowest point or at the navel if unclear, after a normal exhale.
Hips (women): Widest point over the buttocks, tape parallel to the floor.

How it’s calculated

Male: Navy %BF from height, neck, waist.
Female: Navy %BF from height, neck, waist, hips.
Outputs are % body fat; track over time under similar conditions (time of day, hydration).

Disclaimer: Anthropometric formulas are estimates and can be off for very lean/very muscular or older individuals. For clinical or precision needs, consider DEXA or multi-compartment methods.

FAQ

Which method does this calculator use?
The US Navy circumference method with sex-specific equations based on waist, neck, hips (women) and height.
How accurate is the Navy method?
It’s a practical field estimate. Expect some error versus lab methods (DEXA, hydrostatic), but it’s consistent for tracking trends if you measure the same way each time.
Why is my % different from a smart scale?
Smart scales use BIA (bioimpedance), which is sensitive to hydration and device algorithms. Different methods yield different estimates.
How often should I check body fat?
Every 2–4 weeks during a program. Take measurements at a similar time of day with consistent tape placement.
What ranges are typical?
Ranges vary by sex and age. Focus on trend over time plus waist/hip measures and performance, not a single number.

Disclaimer

The tools provided on this site are intended for educational and informational purposes only and are not a substitute for professional medical advice, diagnosis, or treatment. Always seek the advice of a qualified health provider with any questions you may have about a medical condition. If you think you may have a medical emergency, call your local emergency number immediately.

Formulas are estimates and may be less accurate for athletes, bodybuilders, older adults, and certain body types.