Calculator

Muscle Mass Calculator

Estimate your skeletal muscle mass from your height, weight and sex.

Built by Menang7, owner of LeanMassCalculator.com

Lean Mass vs Muscle Mass →
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Guide

Lean Body Mass vs Muscle Mass

Muscle is only part of your lean mass. Learn what each number includes and which one to track.

Read the guide →

How muscle mass is estimated

Direct measurement needs a DXA scan, MRI or a bioimpedance device. This calculator works in two steps. First it finds your lean body mass, either from your body fat percentage if you enter it, or with the Boer formula from your height, weight and sex.

Then it estimates skeletal muscle as a share of lean mass: about 50% for men and 44% for women, with a margin of roughly five percentage points either side. The rest of lean mass is bone, organs, skin and water. Treat the result as a rough guide and track the trend over time.

Typical skeletal muscle share of body weight

CategoryWomenMen
Lower than typicalBelow 24%Below 33%
Typical24–33%33–42%
Higher than typicalAbove 33%Above 42%

A rough guide for healthy adults. Age, training and body fat all shift where a person falls.

What counts as muscle mass

Skeletal muscleThe muscles attached to bones that you use to move, lift and stay upright. This is what the calculator estimates.
Smooth muscleMuscle in organs such as the gut and blood vessels. You do not control it directly.
Cardiac muscleThe heart muscle. It is part of lean mass but not part of skeletal muscle.
Not muscleBone, organs, skin and water also sit inside lean mass, which is why the two numbers differ.

How to build muscle mass

Lift with progressionTrain each muscle at least twice a week and add load or reps over time.
Eat enough proteinAbout 1.6–2.2 g per kg of lean mass daily.
Eat enough overallA small calorie surplus of 5–10% supports growth without adding much fat.
Sleep 7–9 hoursRecovery is when muscle is repaired and built.
Stay consistentVisible change takes months, so measure monthly under the same conditions.
Keep movingDaily walking protects muscle and bone as you age.

Frequently asked questions

What is skeletal muscle mass?
It is the muscle you control to move your body. It is only one part of lean mass, which also includes bone, organs, skin and water.
How accurate is this calculator?
It is a rough estimate that can be off by several kilograms. A DXA or bioimpedance scan gives a more precise reading.
Is lean mass the same as muscle mass?
No. Lean mass is everything that is not fat, and muscle is one part of it. Read the guide on lean body mass vs muscle mass for the full breakdown.
How can I increase my muscle mass?
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.
Why does my result differ from a smart scale?
Smart scales use electrical impedance, which shifts with hydration, and each brand defines muscle slightly differently. Compare readings from the same device over time.
Is lean mass the same as muscle mass? Read more →

Related

🧮Body Fat CalculatorEstimate your body fat percentage from height, weight, age and sex.Open →🥩Protein Intake CalculatorFind a daily protein target based on your lean mass and goal.Open →📏Lean Mass Index (LMI)Lean mass divided by height squared: a fairer way to compare builds.Open →🧮Lean Mass CalculatorEstimate your lean body mass from height, weight, age and sex.Open →📝Healthy Lean Mass Percentage by AgeWhat is normal at 20, 40 and 60, and what to aim for.Open →🧰All ToolsEvery calculator in one place.Open →

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.