Body Composition
Calculate your BMI and estimate your body-fat percentage using the U.S. Navy method, a quick, tape-measure-based assessment of where you stand.
Measure with a soft tape, relaxed, at the widest point of the waist/hip and below the larynx for the neck.
Body fat uses the U.S. Navy circumference method, a solid estimate, but a weekly in-studio measurement is far more accurate. BMI ignores muscle mass, so athletes often read “overweight.”
Want your body composition tracked weekly?
These are estimates. We build yours from weekly data, not formulas.
The method behind the numbers
- 1
Enter your height, weight, and a few tape measurements (neck and waist, plus hip for women).
- 2
BMI is calculated from height and weight as a quick population-level reference.
- 3
Body-fat percentage is estimated with the U.S. Navy circumference method, which uses your measurements to gauge composition, not just total weight.
- 4
You get both numbers with categories, so you can see why a muscular person can read 'overweight' on BMI yet have low body fat.
Common questions
How accurate is the Navy body-fat method?+
The U.S. Navy circumference method is a solid, repeatable estimate, usually within a few percent of a DEXA scan when you measure consistently. For a precise figure, our coaches take weekly in-studio measurements.
Why is BMI misleading for athletes?+
BMI only uses height and weight, so it can't tell muscle from fat. A lean, muscular person often reads 'overweight' on BMI despite low body fat, which is why body-fat percentage is the more useful metric.
How should I take the measurements?+
Use a soft tape, relaxed, measuring the waist at the widest point, the hip at the widest point, and the neck just below the larynx. Measure at the same time of day for consistency.
You have the numbers. Here's what to do with them.
A calculator tells you where you stand. Our free guide shows you how to act on it, and a free consultation turns it into a plan built around you.