Body Fat Calculator: Estimate Body Fat Percentage

Free body fat percentage calculator

Body fat percentage estimates what portion of body weight is fat mass. Unlike BMI, it uses body measurements instead of only weight and height. The result can be useful for tracking change over time, especially when measured consistently.

This calculator uses the U.S. Navy circumference method. It is still only an estimate. Tape placement, posture, hydration, bloating, and measurement error can change the result.

Measurement tips

Use a flexible tape measure.
Measure at the same time of day when possible.
Keep the tape level and snug, not tight.
Repeat each measurement twice and use the average if needed.

How to use your body fat estimate

Focus on trends, not a single reading. If your measurement technique changes, the number may jump even when your body has not changed much. Measure under similar conditions and pair the result with energy, strength, waist size, and health markers.

Example

A male who is 70 in tall with a 36 in waist and 16 in neck receives an estimate based on the relationship between those measurements and height. A female calculation also includes hip circumference.

Frequently asked questions

How accurate is the body fat calculator?

It is an estimate based on tape measurements. Accuracy depends heavily on measuring consistently and correctly.

Which formula is used?

This calculator uses the U.S. Navy circumference method for adults.

Where should I measure?

Measure waist, neck, and hip as instructed on the form. Keep the tape level and snug but not compressing the skin.

Is this better than BMI?

It gives different information. BMI compares weight to height; body fat estimates use circumferences. Both are estimates with limitations.

Can pregnancy affect the result?

Yes. Pregnancy changes waist and body composition. This calculator is not intended for pregnancy assessment.