Health & fitness
Body fat estimate
Estimate body-fat percentage from BMI, age and sex coefficient.
Calculators / Health & fitness / Lean body mass
Lean body mass calculator
Estimate lean mass from body weight and an entered body-fat percentage.
On this page
Lean body mass64same weight unit
Fat mass16same weight unit
Calculator controls
How to calculate
Estimate lean mass from body weight and an entered body-fat percentage.
Lean body mass = weight*(1-fat/100); Fat mass = weight*fat/100
Worked example
Body weight: 80; Body fat (%): 20.
Lean body mass: 64 same weight unit; Fat mass: 16 same weight unit.
Assumptions and limits
Accuracy is limited by the body-fat measurement or estimate supplied.
Results are rounded for display; calculations use unrounded values. Read our calculation methodology.
Understanding the result
Estimate lean mass from body weight and an entered body-fat percentage. The displayed figures use the inputs and formula shown on this page.
When this tool is useful
Use the lean body mass to compare a scenario, check an estimate, or verify a manual calculation.
Understanding your inputs
| Input | What to enter |
|---|---|
| Body weight | Enter a number of at least 0.000001 and no more than 1000000000000. |
| Body fat (%) | Enter a number of at least 0 and no more than 100. |
Frequently asked questions
What should I check before using the lean body mass result?
Accuracy is limited by the body-fat measurement or estimate supplied.
Is this lean body mass result exact?
It is exact for the stated mathematical model and entered values. Real-world results can differ when rates, timing, fees, definitions or measurement conditions differ.