BMR from Lean Mass
Fat tissue is nearly inert metabolically, so working from lean mass alone avoids underestimating people who carry a lot of muscle.
Your numbers
BMR
1,558kcal
TDEE
2,415kcal
Formula
BMR = 370 + 21.6 × Lean mass
This only helps if you have a measured body fat percentage — otherwise use Mifflin-St Jeor.
What to enter
| Input | Default | Accepted range |
|---|---|---|
| Lean mass (kg)Everything that is not fat — muscle, bone, water. | 55 | 5 ~ 200 |
Step by step
Quick reference table
Results when only Lean mass (kg) changes and everything else stays put.
| Lean mass (kg) | BMR (kcal) | TDEE (kcal) |
|---|---|---|
| 27.5 | 964 | 1,494 |
| 41.3 | 1,262 | 1,956 |
| 55 | 1,558 | 2,415 |
| 82.5 | 2,152 | 3,336 |
| 110 | 2,746 | 4,256 |
What each result means
| Result | At default values |
|---|---|
| BMR (kcal)The calories you burn in a day doing nothing at all. | 1,558 |
| TDEE (kcal)Daily calories burned once activity is included. | 2,415 |
Common mistakes
This only helps if you have a measured body fat percentage — otherwise use Mifflin-St Jeor.
Glossary
- Lean mass
- Everything that is not fat — muscle, bone, water.
- BMR
- The calories you burn in a day doing nothing at all.
- TDEE
- Daily calories burned once activity is included.
Frequently asked questions
Q. How is BMR from Lean Mass calculated?
BMR = 370 + 21.6 × Lean mass — Fat tissue is nearly inert metabolically, so working from lean mass alone avoids underestimating people who carry a lot of muscle.
Q. Can you walk through an example?
With Lean mass 55kg, the answer is BMR 1,558kcal.
Q. What do I need to enter?
Enter Lean mass. The result recalculates as you type, and an empty box counts as zero.
Q. How much does the answer move if I change a number?
Changing only Lean mass (kg) moves the answer to Lean mass (kg) 27.5 → BMR (kcal) 964 and Lean mass (kg) 110 → BMR (kcal) 2,746. The table below lays out five steps.
Q. How are the numbers rounded?
Money is shown to the nearest whole unit, percentages to one decimal place and everything else to two. What you see is rounded; the calculation itself carries the unrounded value forward.
Q. Anything to watch out for?
This only helps if you have a measured body fat percentage — otherwise use Mifflin-St Jeor.
Related calculators
These calculators help you understand health figures; they do not replace diagnosis or prescription. See a clinician if you have symptoms.