Body Fat Percentage Calculator
Estimate adult body-fat percentage from height and tape measurements using the U.S. Navy circumference equation. The result also shows fat mass, fat-free mass, and measurement sensitivity.
Written and checked by TheToolNet Editorial Team · Last reviewed: September 27, 2026 · Editorial method
This result is a general educational estimate, may be inaccurate for you, and is not medical advice or a diagnosis. Consult a qualified doctor or other appropriate licensed clinician before using it for treatment, diet, exercise, medication, pregnancy care, or a personal health target.
Estimate body fat with a tape measure
Measurement method matters
Use a non-stretch tape, keep it level, and measure under the same conditions each time. Do not pull the tape hard enough to compress the skin. The official Navy body-composition guide describes its measurement sites and procedures.
Male and female equations use different sites
The male equation uses height, neck, and abdomen or waist. The female equation also uses hip circumference. Select the matching equation and follow a single measurement protocol consistently; mixing sites from different protocols makes comparisons unreliable.
Why the calculator shows a ±1 cm range
Tape placement, posture, breathing, and tension can move a circumference measurement. The sensitivity output recalculates the estimate with the waist one centimeter lower and higher, making that measurement dependence visible.
Body-fat estimate versus BMI
BMI uses only height and weight. A circumference equation tries to approximate body composition, but neither is a direct measurement. Compare the metric adult BMI calculator if you need that separate screening value.
What this result cannot determine
The estimate does not diagnose health, set a safe target, or replace DEXA, air-displacement plethysmography, underwater weighing, or a clinician-guided assessment. Hydration and recent training can also affect some other body-composition methods.
Frequently asked questions
Is this an official military qualification result?
No. It is an educational implementation of a circumference equation. Current service rules, authorized measurement procedures, tables, rounding, and appeals govern official decisions.
Should I compare results from different methods?
Different methods can produce different percentages. For tracking, use one method, comparable conditions, and the same measurement sites.