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

Lean mass(kg)

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

FormulaBMR = 370 + 21.6 × Lean mass

With the default numbersBMR = 370 + 21.6 × 55

AnswerBMR = 1,558 kcal

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

QHow 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.

QCan you walk through an example?

With Lean mass 55kg, the answer is BMR 1,558kcal.

QWhat do I need to enter?

Enter Lean mass. The result recalculates as you type, and an empty box counts as zero.

QHow 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.

QHow 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.

QAnything to watch out for?

This only helps if you have a measured body fat percentage — otherwise use Mifflin-St Jeor.

Related calculators

BMR CalculatorFind the minimum calories your body burns doing nothing at all.TDEE CalculatorMultiply BMR by an activity factor for total daily calories burned.Calorie Deficit CalculatorSet daily intake to match the rate of weight loss you want.Weight Loss TimelineSee how many weeks reaching your goal weight will take.

These calculators help you understand health figures; they do not replace diagnosis or prescription. See a clinician if you have symptoms.