Estimate lean body mass
Estimate fat-free (lean) body mass and fat mass from height, weight, and sex, using the Boer formula.
Uses the Boer formula, which estimates fat-free mass from height and weight alone. It's a population-level estimate, not a substitute for a body composition scan.
Switch between metric (cm, kg) and imperial (ft/in, lb) with the units toggle.
Uses the Boer formula, which estimates fat-free mass from height and weight alone.
Your estimated fat mass and lean mass percentage are shown alongside your lean body mass.
Frequently asked
What is lean body mass?
Everything in your body that isn't fat, including muscle, bone, organs, and water. Estimating it separates "how much of my weight is fat" from "how much is everything else."
How accurate is the Boer formula?
It's a population-level estimate based on height and weight alone, so it won't match a body composition scan (DEXA, BIA, etc.) exactly, but it's a reasonable general estimate.
Is this medical advice?
No. This is a general estimate for informational purposes only, not medical advice. Talk to a healthcare provider or certified trainer before changing your training or diet.