Formulas
| Formula | Men | Women |
|---|---|---|
| Boer (1984) | 0.407 × W + 0.267 × H − 19.2 | 0.252 × W + 0.473 × H − 48.3 |
| James (1976) | 1.1 × W − 128 × (W ÷ H)² | 1.07 × W − 148 × (W ÷ H)² |
| Hume (1966) | 0.32810 × W + 0.33929 × H − 29.5336 | 0.29569 × W + 0.41813 × H − 43.2933 |
W = weight in kg, H = height in cm. The Boer formula is the most widely used for adults.
Why lean mass matters
Muscle burns more energy than fat, protects your joints and keeps blood sugar steady. When you diet, the goal is to lose fat while keeping lean mass. Eating enough protein and doing strength training are the two best ways to protect it.
Frequently asked questions
What is a normal lean body mass?
Lean mass is usually about 75–85% of body weight in men and 65–80% in women, depending on fitness.
Is lean body mass the same as muscle mass?
No. Lean body mass includes muscle plus bone, organs, skin and water. Muscle is the largest part.
How can I increase lean body mass?
Do progressive strength training, eat 1.6–2.2 g of protein per kg of body weight and sleep 7–9 hours.
Sources
- Boer P. Estimated lean body mass as an index for normalization of body fluid volumes in humans. American Journal of Physiology, 1984.
- James WPT. Research on obesity. Her Majesty's Stationery Office, 1976; Hume R. Prediction of lean body mass from height and weight. Journal of Clinical Pathology, 1966.
Medical disclaimer: This calculator gives estimates for general information only. It is not a diagnosis or a substitute for advice from a doctor or registered dietitian. Please consult a healthcare professional before making changes to your diet, exercise or medicines, especially if you are pregnant, have a medical condition or take regular medication.
Last updated: 20 October 2026. Read our editorial policy.
