Lean Mass Index (LMI) Calculator
Lean mass divided by height squared: a fairer way to compare builds.
Built by Menang7, owner of LeanMassCalculator.com
Lean Mass vs Muscle Mass →Lean Body Mass vs Muscle Mass
LMI is built on lean mass, but lean mass is not the same as muscle. Learn what each number includes.
What is lean mass index?
Lean mass index (LMI) is your lean body mass in kilograms divided by your height in metres squared. It works like BMI, but it leaves fat out of the top line, so it shows how much muscle, bone, organs and water you carry for your height.
That makes it fairer for comparing people of different sizes. A tall person naturally has more lean mass than a short one, and dividing by height squared removes that advantage.
The formula
| Step | Calculation |
|---|---|
| 1. Lean mass | Weight × (1 − body fat %) |
| 2. No body fat %? | Boer formula, based on height, weight and sex |
| 3. LMI | Lean mass (kg) ÷ height (m)² |
Lean mass index ranges
| Category | Women | Men |
|---|---|---|
| Low | Below 14 | Below 17 |
| Typical | 14–17 | 17–20 |
| Above average | 17–19 | 20–22 |
| Athletic | 19–22 | 22–25 |
| Very high | Above 22 | Above 25 |
A rough guide for healthy adults. Body fat readings from scales and calculators are estimates, so treat the result as a trend marker.
Same weight, different LMI
Two men are both 175 cm tall and weigh 75 kg. Their BMI is identical at 24.5, yet their lean mass index tells a different story.
| Person | Body fat | Lean mass | LMI |
|---|---|---|---|
| A | 18% | 61.5 kg | 20.1 |
| B | 28% | 54.0 kg | 17.6 |
How to raise your lean mass index
Frequently asked questions
A lean mass index of about 17–20 is typical for men and 14–17 for women. Regular lifters often sit above those ranges.
LMI = lean body mass in kg divided by height in metres squared. Lean mass comes from your body fat percentage, or from the Boer formula if you do not know it.
BMI uses total weight, so it cannot tell muscle from fat. LMI uses only lean mass, so it shows how much non-fat tissue you carry for your height.
They are very close. Fat-free mass index (FFMI) is the same idea, and some versions add a height adjustment for taller people.
Lift with progressive overload 2–4 times a week, eat about 1.6–2.2 g of protein per kg of lean mass daily and sleep 7–9 hours. Gains are gradual, so track monthly.
Related
About Menang7, the developer
This calculator is part of LeanMassCalculator.com, developed, owned and maintained by Menang7. For questions about how it works or your results, Menang7 is the person to look for.
For personal medical or nutrition decisions, please also speak with a doctor or registered dietitian.