How accurate is the Navy method?

The US Navy method is a tape-measure estimate, not a lab test. It can be consistent for tracking trends if you measure the same way each time, but it can vary based on tape placement and how tight you pull the tape.

Where should I measure my waist?

Measure your waist at the navel (belly button), standing relaxed. Keep the tape level and snug without compressing the skin, and take two measurements to confirm.

How often should I measure body fat?

For most people, every 2 to 4 weeks is enough. Daily changes can be noise from hydration and measurement technique, so focus on long-term trends.

Free toolNavy methodTape measurementsUS/metric units

Navy Body Fat Calculator

Use this body fat percentage calculator (Navy method) to estimate body fat from simple tape measurements. Enter your height, neck, waist, and hip if applicable, and the tool applies the US Navy body fat formula. Follow the measurement tips for consistency. Results are estimates and can vary by technique, so track trends over time. Not medical advice. Methodology.

Methods & assumptions

This variant focuses on Navy Body Fat Calculator.

What this body fat calculator estimates

This tool estimates body fat percentage using the US Navy body fat formula (also called the Navy method). It uses your height, neck, waist, and hip (if applicable) from a tape measure. The result is an estimate — use it to track trends, not as a diagnosis.

Where to measure

Waist: measure at your navel (belly button).
Neck: measure just below the larynx (Adam's apple).
Hips: measure at the widest point of the glutes (required for females/women and other/prefer not to say).

Formulas (Navy method)

Inputs are converted to inches for the logarithms. We round the final body fat percentage to one decimal place.

Male: 86.010 * log10(waist - neck) - 70.041 * log10(height) + 36.76
Female: 163.205 * log10(waist + hip - neck) - 97.684 * log10(height) - 78.387
Other/Prefer not: compute both and average

Body fat percentage categories (by sex)

Category bands differ for men and women. If you choose other / prefer not to say, we show both category bands.

Sex	Essential	Athletes	Fitness	Average	Obese
Male	2–5%	6–13%	14–17%	18–24%	≥ 25%
Female	10–13%	14–20%	21–24%	25–31%	≥ 32%

Male

Essential2–5%

Athletes6–13%

Fitness14–17%

Average18–24%

Obese≥ 25%

Female

Essential10–13%

Athletes14–20%

Fitness21–24%

Average25–31%

Obese≥ 32%

How to use this result

Measure at the same time of day, use the same tape placement, and focus on long-term trends. If you have symptoms or concerns, contact a healthcare professional.