Keto Calculator
Keto macros.
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Fitness
Lean Body Mass Calculator
Estimate lean mass and fat mass from height, weight and sex.
Lean body mass
—
Boer formula.
| Body fat mass | — |
|---|---|
| Lean % | — |
| Weight | — |
| — |
Show our math
Enter your figures above to see the step-by-step working.
Everything computed client-sideEverything computed client-side — nothing leaves this page
How the Lean Body Mass Calculator Works
Lean body mass is everything in your body that isn’t fat — muscle, bone, organs and water. This calculator uses the Boer formula, one of the most accurate estimates from height and weight, and subtracts the result from your total weight to give your fat mass and lean percentage.
Lean body mass is useful for setting protein targets, dosing medication and tracking body composition, since it changes far less than total weight when you gain or lose fat.
Boer (men): 0.407×kg + 0.267×cm − 19.2
Frequently Asked Questions
What is lean body mass?
Your total weight minus body fat — muscle, bone, organs and water. It’s a better training and health marker than weight alone.
How is lean body mass calculated?
From height and weight using a validated formula such as Boer, Hume or James. This calculator uses the Boer formula.
Why does lean body mass matter?
It guides protein intake and medication dosing, and tracking it shows whether weight change is fat or muscle.
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