Lean Body Mass
58.0 kg
Fat Mass (est.)
17.0 kg
Method
Boer
Body & Fitness
Lean Body Mass Calculator
Estimate lean body mass (LBM) using height, weight, and sex-based formulas.
By Calculator Suite Pro Editorial Team | Last updated March 18, 2026
Browse more tools in All Tools.
On this page
Jump to examples, FAQs, and detailed explanations without endless scrolling.
Direct answer
Lean Body Mass Calculator gives an instant result from your inputs. Lean body mass (LBM) estimates how much of your body weight is not fat. It includes muscle, bone, organs, and water. LBM can be helpful for understanding body composition trends. Formula snapshot: LBM is estimated from weight and height using sex-specific coefficients. Example: Sex: Men, Weight: 80kg, Height: 180cm -> LBM estimate shown (kg).
About this calculator
Lean body mass (LBM) estimates how much of your body weight is not fat. It includes muscle, bone, organs, and water. LBM can be helpful for understanding body composition trends.
This calculator uses common height- and sex-based formulas to estimate LBM from weight and height. It is an estimate, not a lab measurement.
If you also estimate body fat percentage, you can compare the two views and track progress more clearly than weight alone.
How it works
A quick explanation of the logic behind the results, so you can trust what you see.
- LBM is estimated from weight and height using sex-specific coefficients.
- We compute lean mass (kg) and you can infer fat mass as total weight minus lean mass (rough estimate).
- Because it is formula-based, accuracy varies by individual.
- Use it as a trend tool rather than an absolute truth.
Formula used
These are the core formulas and logic rules used by this calculator.
- LBM is estimated from weight and height using sex-specific coefficients.
- Because it is formula-based, accuracy varies by individual.
Common use cases
Below are common real-world scenarios where this calculator is useful.
- Tracking recomposition (muscle gain vs fat loss)
- Setting strength and fitness goals
- Understanding weight changes (lean vs fat trend)
- Nutrition planning context (protein targets)
- Comparing progress beyond BMI
- Fitness coaching check-ins
- Estimating lean mass for training planning
- Trend tracking across months
How to use
- Select sex.
- Enter weight and height.
- Calculate to see estimated LBM (kg).
- Compare with total weight to understand fat mass trends.
- Track changes over time under similar conditions.
Common mistakes to avoid
These are the issues that most often cause confusing results.
- Treating LBM estimate as exact muscle mass (LBM includes more than muscle).
- Entering height/weight in the wrong units.
- Comparing results across different formulas without context.
- Focusing on a single reading instead of trend over time.
- Using it for medical decisions without professional guidance.
Tips and notes
- Use LBM trends along with body fat percentage for a fuller picture.
- If you are strength training, focus on performance and measurements, not only formulas.
- For calorie targets, use TDEE and adjust based on weekly progress.
- Measure under consistent conditions for the most useful trend tracking.
Glossary
Quick definitions for common terms used in this calculator.
LBM
Lean Body Mass: the non-fat portion of body weight.
Fat mass
The portion of body weight that is fat tissue (estimated, not measured here).
Examples
Example
Input: Sex: Men, Weight: 80kg, Height: 180cm
Output: LBM estimate shown (kg)
Example
Input: Sex: Women, Weight: 60kg, Height: 165cm
Output: LBM estimate shown (kg)
Recomposition
Input: Weight stable, LBM estimate increases
Output: Potential positive trend (estimate)
FAQ
Is lean body mass the same as muscle mass?
No. Lean body mass includes muscle plus bone, organs, and water. It is broader than muscle mass.
How accurate is LBM from formulas?
It varies by individual. Use it mainly to track trends rather than exact numbers.
Can I estimate fat mass from LBM?
Roughly: fat mass = total weight - LBM. But both values are estimates, so treat it as directional.
Should I use this for medical dosing?
No. Use professionally validated methods and consult clinicians for dosing decisions.
Does sex matter?
Yes. The formulas use sex-specific coefficients.
Can athletes use this?
Yes as a trend estimate, but athletes can differ more from formula assumptions.
Is this calculator free to use?
Yes. This calculator is free to use without signup.
Can I use this calculator on mobile?
Yes. The calculator is mobile-friendly and works on desktop as well.
Last updated and references
Last updated: March 18, 2026
Reviewed by Calculator Suite Pro Editorial Team.
For sensitive health and finance topics, review official sources in addition to calculator outputs.
Related calculators
Explore related tools to solve similar problems without leaving the site.
BMI Calculator
Calculate BMI (Body Mass Index) and view the category range.
Body Fat Percentage Calculator
Estimate body fat percentage using measurement-based formulas (US Navy method).
BMR Calculator
Calculate Basal Metabolic Rate (BMR) using the Mifflin-St Jeor formula.
TDEE Calculator
Estimate daily calorie needs (TDEE) based on BMR and activity level.
Age Calculator
Calculate exact age in years, months, and days from date of birth.
Date Difference Calculator
Find the duration between two dates (years, months, days and total days).