Skip to content
OneKitly
Sign up · Sign in

Lean body mass calculator

Estimate your lean body mass and fat mass from weight, height and sex.

Related tools

All Weight & body tools →
Body fat calculatorEstimate your body fat percentage (U.S. Navy method).Body Frame Size CalculatorSmall, medium or large frame from your height-to-wrist ratio, with a frame-adjusted weight range.Body surface area calculatorCompute your body surface area (BSA) with the five published formulas — Mosteller, Du Bois, Haycock, Gehan & George and Boyd — side by side.Lean Body Mass to Strength CalculatorPredict your squat, bench and deadlift from lean mass, and score how much of that potential you've realised.Ideal weight calculatorEstimate your ideal body weight (Devine formula).Daily calorie calculator (TDEE)Estimate your daily calorie needs to maintain, lose or gain weight.BMI calculatorCompute your Body Mass Index and weight category.Target weight for a BMI calculatorFind the body weight that matches a target BMI for your height.

Need Lean body mass (kg), Fat mass (kg)? The Lean body mass calculator derives it from Weight (kg), Height (cm), Sex in one step. For instance, with Weight (kg) = 70, Height (cm) = 175 and Sex = Male it returns Lean body mass (kg) = 56.015 and Fat mass (kg) = 13.985.

How to use it

  1. Enter your values: Weight (kg), Height (cm), Sex.
  2. Read the result instantly: Lean body mass (kg), Fat mass (kg).

Frequently asked questions

What does the Lean body mass calculator actually compute?

It takes Weight (kg), Height (cm) and Sex and derives Lean body mass (kg) and Fat mass (kg) from them. The calculation is live as you type, so the result updates on every change.

What information do I need to provide?

3 values: Weight (kg), Height (cm) and Sex. Nothing else is required — no account, no file upload.

Can you show a worked example?

With Weight (kg) = 70, Height (cm) = 175 and Sex = Male, the calculator returns Lean body mass (kg) = 56.015 and Fat mass (kg) = 13.985. Those figures come from running this exact tool, so you can reproduce them by entering the same values.

What happens if I enter larger values?

It moves a lot. Using Weight (kg) = 77, Height (cm) = 193 and Sex = Female instead, Lean body mass (kg) goes from 56.015 to 62.393 — which is why it is worth testing a few scenarios rather than trusting a single figure.

Which “Sex” option should I choose?

You can pick between « Male » and « Female ». Each one changes what the calculator works out, so switch and compare — the default is « Male ».

What does it give for smaller values?

Scaled down to Weight (kg) = 63, Height (cm) = 158 and Sex = Male, Lean body mass (kg) comes out at 48.627. The relationship is worth checking at both ends before you rely on a single result.

When would I actually use this?

Getting a reference point before a check-up, setting a realistic target, and understanding why two people of the same weight can be in very different shape — and, the same act from the other side, putting a day's caffeine, salt, sugar or alcohol beside the ceiling a health body publishes for it.

What is the most common mistake?

Reading BMI as a measure of health. It cannot tell muscle from fat, which is why athletes routinely score as overweight and why it says little about an individual.

How accurate is it, and what are the limits?

For general guidance only — not medical advice.

What is the difference between the Lean body mass calculator and the Body fat calculator?

This one returns Lean body mass (kg) and Fat mass (kg); the Body fat calculator returns Body fat. That is the whole difference — open the one whose figure you need.

Further reading

All guides →
ExplainerWhat Is Lean Body Mass? LBM vs Fat MassLean body mass is everything in your body that isn't fat. Learn how the Boer formula estimates it and why it matters for health and training.ExplainerIs BMI Reliable? The Limitations of Body Mass IndexBMI is a quick screen, not a diagnosis. Learn what it misses — muscle, fat distribution, age — and what to check alongside it.ExplainerBody Frame Size, and What Ideal-Weight Formulas AssumeFrame size exists because height alone does not fix skeletal mass, and the published methods are crude proxies with real cut-offs. The bigger story is the ideal-weight formulas: four of them, all built for drug dosing rather than health, disagreeing by up to 27 lb at the same height.ExplainerWhat Is a Good Body Fat Percentage?Body fat percentage is a better health signal than weight alone. Here are the healthy ranges by sex, how it's measured, and how to use it wisely.ExplainerWaist-to-Hip Ratio Explained: The Thresholds, and Where to Put the TapeWHO puts abdominal obesity at a ratio of 0.90 or more for men and 0.85 or more for women. But measuring in the wrong place changes the answer more than the threshold does — here is exactly where the tape goes.ExplainerWhat Is a Child Growth Percentile?Growth percentiles compare a child's height and weight to others the same age and sex. Here's how to read them and what really matters.