Body & Fitness

Body Fat Percentage Calculator

Estimate body fat percentage using measurement-based formulas (US Navy method).

By Calculator Suite Pro Editorial Team | Last updated March 18, 2026

Use this estimate as body-metric context, then compare nearby fitness tools when one number needs more perspective.

Explore the Body & Fitness group for nearby calculators, examples, and guide links.

SexHeight (cm)

Waist (cm)Neck (cm)

Body Fat %

12.0%

Method

US Navy

Note

Estimate

Use trends, not a single number.

About this calculator

Body fat percentage estimates how much of your body weight is fat mass compared to total weight. Unlike BMI, body fat percentage aims to describe body composition more directly.

This calculator uses the popular measurement-based US Navy method. It requires tape measurements (waist, neck, height, and hip for women). The result is an estimate, not a medical diagnosis.

For best accuracy, measure in the morning, keep the tape level, and avoid pulling it too tight. Small measurement changes can noticeably affect the result.

How the estimate is calculated

A short explanation of how the body or training inputs are turned into an estimate.

The US Navy method estimates body density based on circumferences and height, then converts density into body fat percentage.
It uses logarithms of measurement combinations (for example, waist minus neck).
Because it is tape-based, the estimate depends strongly on consistent measuring technique.
This method is widely used for quick screening but can differ from DEXA, calipers, or hydrostatic tests.

Formula and interpretation limits

These are the formulas, assumptions, and screening limits used by this body or fitness calculator.

It uses logarithms of measurement combinations (for example, waist minus neck).
This method is widely used for quick screening but can differ from DEXA, calipers, or hydrostatic tests.

Where this estimate can help

Use these scenarios to decide whether the output is useful for tracking, planning, or a basic screen.

Tracking body composition progress over time
Comparing fat loss phases vs maintenance phases
Setting realistic fitness goals
Estimating lean mass when paired with body weight
Checking progress beyond a scale number
Fitness coaching and check-ins
General health awareness (non-diagnostic)
Complementing BMI with a composition estimate

How to enter body metrics

Select sex (men/women) because the formula differs.
Enter waist, neck, and height measurements.
If applicable, enter hip measurement (women).
Calculate to see estimated body fat percentage.
Re-check your measurements if the number looks unusually high/low.

Body-metric mistakes to avoid

Confusing results usually come from measurement errors, formula assumptions, or over-interpreting a single number.

Measuring at different spots each time (inconsistent waist/neck location).
Pulling the tape too tight or leaving it too loose.
Not keeping the tape level around the body.
Entering height/waist/hip in the wrong units.
Using the men's formula for women or vice versa.
Comparing with other methods and expecting identical numbers (methods differ).

Interpretation tips

Measure at the same time of day for consistent tracking.
Take 2-3 measurements and use the average to reduce error.
Use this number mainly to track trends, not as a one-time verdict.
Pair with Lean Body Mass calculator if you want a rough lean-mass estimate from weight.
If you want a simpler screening metric, check Waist-to-Height Ratio too.

Glossary

Quick definitions for body and fitness terms used on this page.

Body composition

The proportions of fat mass and lean mass in the body.

US Navy method

A tape-measurement based method to estimate body fat percentage.

Body-metric examples

Men example

Input: Sex: Men, Height: 180cm, Waist: 90cm, Neck: 40cm

Output: Estimated body fat % shown

Women example

Input: Sex: Women, Height: 165cm, Waist: 75cm, Hip: 95cm, Neck: 35cm

Output: Estimated body fat % shown

Trend tracking

Input: Repeat weekly with same measurement points

Output: Compare changes in % over time

Body and fitness guides

Related explainers that add context around formulas, trends, and interpretation limits.

Browse all articles

FAQ

Is body fat percentage more accurate than BMI?

It can be more descriptive for body composition, but it is still an estimate. BMI and body fat percentage measure different things.

Why does the calculator ask for neck measurement?

The US Navy method uses neck circumference as part of the density estimate.

Do I need hip measurement?

Hip is used in the women's US Navy formula. Men typically do not need hip measurement for this method.

How accurate is this method?

It is a useful estimate for many people, but results can differ from lab methods. Use it mainly for consistent trend tracking.

Can I use this if I lift weights and have more muscle?

Yes. The method is measurement-based, but any single method can still be imperfect for individuals.

Does hydration affect results?

Hydration can affect body measurements slightly. Measuring under similar conditions improves consistency.

Body-metric references and update notes

Last updated: March 18, 2026

Reviewed by Calculator Suite Pro Editorial Team.

Use the output for general context; clinical or high-stakes decisions need professional confirmation.

Related body and fitness calculators

Use nearby body-metric tools together when one estimate needs more context.