Tape-measure body fat estimate

Navy Body Fat Calculator

Estimate body fat percentage with the US Navy circumference method. Enter height, neck, waist, and hip measurements to get a fast tape-test estimate without uploading a photo.

This tool is for personal fitness tracking and education. Official Navy BCA results are determined by the current Navy process, tables, and PRIMS entry.

Calculate Navy Body Fat

Choose sex, enter measurements in inches, then calculate your estimated body fat percentage.

Use a flexible tape and measure to the nearest tenth of an inch for personal tracking.
Navy method Uses the common circumference equations for men and women.
Fast inputs Only height plus tape measurements are required.
Privacy-first The calculator runs in your browser and does not upload measurements.
Clear limits Explains when tape estimates can differ from clinical tests.

How the Navy Body Fat Formula Works

The classic Navy method is a circumference-based estimate. Men use waist, neck, and height. Women use waist, hip, neck, and height. All measurements are entered in inches and the calculator applies base-10 logarithms.

Male formula
Body fat % = 86.010 × log10(waist - neck) - 70.041 × log10(height) + 36.76
Female formula
Body fat % = 163.205 × log10(waist + hip - neck) - 97.684 × log10(height) - 78.387
Why it is useful: The Navy body fat calculator gives a practical body-composition estimate when you have a tape measure but no calipers, DEXA scan, or photo-based AI estimate.

Example Navy Method Calculations

These examples show how different circumference inputs change the result.

Male example

70 in height, 15 in neck, 34 in waist

A common athletic-to-moderate example where waist minus neck drives most of the estimate.

Female example

65 in height, 13 in neck, 29 in waist, 39 in hip

The female equation adds waist and hip, subtracts neck, then adjusts by height.

Tracking example

Same height, smaller waist over time

When measuring conditions stay consistent, the tool can help track directional changes.

When to Use This Calculator

Use the Navy body fat calculator when you want a tape-based estimate that complements BMI, photos, and other body-composition checks.

Compare against BMI

BMI uses only height and weight. The Navy method adds circumference, so it can give more context for muscular or differently shaped bodies.

Track fitness progress

Repeated measurements under similar conditions can show whether waist, neck, and hip changes are moving in the expected direction.

Prepare for a tape test

The calculator helps you understand the inputs behind a tape estimate before reading the official rules for your situation.

Navy Body Fat Calculator FAQ

AI Body Fat Calculator

Estimate body fat from a photo when you want a visual body-composition check.

Try photo estimate

BMI Calculator

Calculate BMI from height and weight, then compare it with circumference-based body fat.

Calculate BMI

Body Fat Estimate Pictures

Learn how visual estimates differ from tape measurements and BMI.

Read the guide