Lean Body Mass Calculator
Estimate lean body mass (muscle + bone + organs) using height and weight.
Lean Body Mass Calculator
Estimate lean body mass (muscle + bone + organs) using height and weight.
Body Mass Index (BMI)
ℹ️ Underweight < 18.5 | Normal 18.5–24.9 | Overweight 25–29.9 | Obese ≥ 30
Disclaimer
Results provided by this calculator are for informational and educational purposes only. They are based on the values you enter and standard formulas, and should not be considered financial, medical, legal, or professional advice. Always consult a qualified professional before making important decisions based on these results. Roughtools makes no warranties regarding the accuracy or completeness of these calculations for your specific situation.
Frequently Asked Questions
Pro Tips
BMI does not distinguish between muscle and fat — athletes routinely register as "overweight." Use BMI alongside waist circumference and body fat percentage for a complete picture.
Waist-to-height ratio (waist ÷ height) below 0.5 is a strong predictor of metabolic health — often more useful than BMI for assessing cardiovascular risk.
Asian populations have higher metabolic risk at lower BMI values. Some clinicians use BMI ≥23 as overweight for Asian adults, not the WHO standard of 25.
Track your BMI trend over months, not as a single snapshot. A consistent downward trend matters far more than hitting a specific number on any given day.
When to Use This Calculator
Calculate your BMI as part of your annual health self-assessment alongside blood pressure and cholesterol.
Find the BMI-normal weight range for your height to set a realistic, medically-recognised target weight.
Check whether BMI is in the healthy range before conceiving — optimal range reduces pregnancy complications.
Monitor BMI monthly during a training program — though note athletes may show high BMI despite low body fat.
Calculate your BMI in advance so you can have an informed conversation about your weight with your healthcare provider.
About the Lean Body Mass Calculator
This lean body mass calculator estimates the weight of all non-fat tissue in your body — muscle, bone, water, and organs — using the Boer, James, and Hume formulas from height and weight, or directly from total weight and body fat percentage if known. Lean body mass is the key driver of metabolic rate and is the basis for accurate protein and calorie prescriptions in athletic and clinical settings.
How to Use the Lean Body Mass Calculator
- 1
Select your sex and enter your height and total weight.
- 2
Optionally enter your body fat percentage if known for the most accurate calculation.
- 3
See estimated lean body mass from Boer, James, and Hume formulas.
- 4
If body fat % is provided: LBM = total weight × (1 − body fat %/100).
- 5
Use LBM for protein calculations (g per kg of LBM) and Katch-McArdle BMR.
Related Calculators
View all →Body Fat Calculator
Estimate body fat percentage using the US Navy method.
BMI Calculator
Calculate Body Mass Index with metric and imperial support. Includes healthy range.
Ideal Weight Calculator
Find your ideal body weight range based on height using multiple formulas.
Protein Calculator
Calculate daily protein needs based on weight, activity level, and fitness goals.
BMR Calculator
Calculate Basal Metabolic Rate — calories your body burns at rest per day.
Your input is processed locally in your browser and is never stored, transmitted, or shared with any server. See our Privacy Policy.