Free online tool

Body Fat Calculator

Enter height, neck, waist, and optional hip measurements with consistent units.

Estimated body fat--
Estimated fat / lean mass-based on entered weight

Adult screening estimate only. It does not replace an individual medical or body-composition assessment.

Method

Health estimate method

BMI uses weight divided by height squared. Energy estimates use the Mifflin-St Jeor equation with the selected activity multiplier, while circumference-based body fat uses the US Navy field formula.

These population formulas are screening and planning estimates, not diagnoses or individual prescriptions. Age, body composition, measurement technique, health, and training can materially change interpretation.

Questions

Body Fat Calculator FAQ

How accurate is the Navy body fat method?

It is a circumference-based estimate. Measurement technique and individual body shape can cause meaningful differences from laboratory methods.

Where should circumference be measured?

Use consistent tape placement and follow the measurement protocol shown by the organization applying the equation.

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