Lean Body Mass Calculator
Use this lean body mass calculator to estimate your LBM, the weight of your body excluding fat mass.
Updated August 8, 2026
Calculated instantly in your browser — nothing is sent to or stored on our servers.
Medical Disclaimer: This calculator provides a general estimate based on established research and is for educational purposes only, not a substitute for medical advice. Individual results can vary based on health conditions, so consult a qualified healthcare professional or registered dietitian before making significant changes to your diet, exercise, or health routine. Read our full Medical Disclaimer.
How Lean Body Mass (LBM) Is Calculated
Lean body mass is your total body weight minus body fat: muscle, bone, organs, and water. It’s a useful baseline for tracking strength and metabolic changes over time, and it’s the input several other calculators on this site build on, most directly the Katch-McArdle path in the TDEE Calculator.
What This Calculator Measures
This estimates lean mass from height and weight alone, without requiring a body fat measurement. If you already know your body fat percentage, that’s a more direct route to the same number, since lean mass is simply your weight times one minus your body fat fraction.
The Formula
This calculator uses the Boer formula¹, developed from a Dutch adult sample and still one of the most widely used height-weight equations for lean mass in clinical settings.
Men: LBM = 0.407 × weight (kg) + 0.267 × height (cm) − 19.2
Women: LBM = 0.252 × weight (kg) + 0.473 × height (cm) − 48.3
How This Calculator Computes Your Result
Enter your sex, height, and weight above. We run the Boer formula directly and also report estimated fat mass as the remainder of your total body weight.
How Boer Compares to Other Formulas
Boer isn’t the only height-weight equation for lean mass. An earlier formula developed from a British sample² tends to produce noticeably lower estimates at typical modern body weights, since it was derived from a smaller, older population.
A more recent equation built from a much larger dataset spanning normal-weight through severely obese adults³ explicitly accounts for the fact that, at very high body weights, additional weight is overwhelmingly fat rather than lean tissue, something the older linear formulas don’t capture. For most people at a typical body weight, the different formulas agree within a few percent of each other, but they diverge more at the extremes.
Why It Matters
Two people can weigh the same yet have very different body composition. Tracking lean mass alongside weight shows whether changes come from muscle or fat. This is a formula-based estimate, and DEXA scans or BIA scales are more precise.
A Note on Accuracy
Boer formula estimates can vary from direct measurement methods by a few kilograms, and different height-weight formulas can disagree with each other, particularly at low or high body weights. Use it to track relative change over weeks, not as a precise clinical value.
Frequently Asked Questions
What is lean body mass?
Lean body mass is your total body weight minus fat mass. It includes muscle, bone, organs, and water, giving a picture of everything that isn't fat.
Which formula does this calculator use?
The Boer formula¹, a well-established equation for estimating lean body mass from height and weight.
Why do different LBM formulas give different results?
Each was built from a different study population using different methods¹,²,³. They tend to agree closely at typical body weights and diverge more at the extremes of height or weight.
Why track lean body mass instead of just weight?
Total weight doesn't distinguish between muscle and fat, so tracking lean mass helps confirm whether weight changes are coming from fat loss or gain versus muscle loss or gain.
Sources
Estimated Lean Body Mass as an Index for Normalization of Body Fluid Volumes in Humans, Boer, 1984
Prediction of Lean Body Mass from Height and Weight, Hume, 1966
Quantification of Lean Bodyweight, Janmahasatian et al., 2005
Lean Body Mass Calculator
Use this lean body mass calculator to estimate your LBM, the weight of your body excluding fat mass.
Updated August 8, 2026
Calculated instantly in your browser — nothing is sent to or stored on our servers.
Medical Disclaimer: This calculator provides a general estimate based on established research and is for educational purposes only, not a substitute for medical advice. Individual results can vary based on health conditions, so consult a qualified healthcare professional or registered dietitian before making significant changes to your diet, exercise, or health routine. Read our full Medical Disclaimer.
How Lean Body Mass (LBM) Is Calculated
Lean body mass is your total body weight minus body fat: muscle, bone, organs, and water. It’s a useful baseline for tracking strength and metabolic changes over time, and it’s the input several other calculators on this site build on, most directly the Katch-McArdle path in the TDEE Calculator.
What This Calculator Measures
This estimates lean mass from height and weight alone, without requiring a body fat measurement. If you already know your body fat percentage, that’s a more direct route to the same number, since lean mass is simply your weight times one minus your body fat fraction.
The Formula
This calculator uses the Boer formula¹, developed from a Dutch adult sample and still one of the most widely used height-weight equations for lean mass in clinical settings.
Men: LBM = 0.407 × weight (kg) + 0.267 × height (cm) − 19.2
Women: LBM = 0.252 × weight (kg) + 0.473 × height (cm) − 48.3
How This Calculator Computes Your Result
Enter your sex, height, and weight above. We run the Boer formula directly and also report estimated fat mass as the remainder of your total body weight.
How Boer Compares to Other Formulas
Boer isn’t the only height-weight equation for lean mass. An earlier formula developed from a British sample² tends to produce noticeably lower estimates at typical modern body weights, since it was derived from a smaller, older population.
A more recent equation built from a much larger dataset spanning normal-weight through severely obese adults³ explicitly accounts for the fact that, at very high body weights, additional weight is overwhelmingly fat rather than lean tissue, something the older linear formulas don’t capture. For most people at a typical body weight, the different formulas agree within a few percent of each other, but they diverge more at the extremes.
Why It Matters
Two people can weigh the same yet have very different body composition. Tracking lean mass alongside weight shows whether changes come from muscle or fat. This is a formula-based estimate, and DEXA scans or BIA scales are more precise.
A Note on Accuracy
Boer formula estimates can vary from direct measurement methods by a few kilograms, and different height-weight formulas can disagree with each other, particularly at low or high body weights. Use it to track relative change over weeks, not as a precise clinical value.
Frequently Asked Questions
What is lean body mass?
Lean body mass is your total body weight minus fat mass. It includes muscle, bone, organs, and water, giving a picture of everything that isn't fat.
Which formula does this calculator use?
The Boer formula¹, a well-established equation for estimating lean body mass from height and weight.
Why do different LBM formulas give different results?
Each was built from a different study population using different methods¹,²,³. They tend to agree closely at typical body weights and diverge more at the extremes of height or weight.
Why track lean body mass instead of just weight?
Total weight doesn't distinguish between muscle and fat, so tracking lean mass helps confirm whether weight changes are coming from fat loss or gain versus muscle loss or gain.
Sources
Estimated Lean Body Mass as an Index for Normalization of Body Fluid Volumes in Humans, Boer, 1984
Prediction of Lean Body Mass from Height and Weight, Hume, 1966
Quantification of Lean Bodyweight, Janmahasatian et al., 2005
Lean Body Mass Calculator
Use this lean body mass calculator to estimate your LBM, the weight of your body excluding fat mass.
Updated August 8, 2026
Calculated instantly in your browser — nothing is sent to or stored on our servers.
Medical Disclaimer: This calculator provides a general estimate based on established research and is for educational purposes only, not a substitute for medical advice. Individual results can vary based on health conditions, so consult a qualified healthcare professional or registered dietitian before making significant changes to your diet, exercise, or health routine. Read our full Medical Disclaimer.
How Lean Body Mass (LBM) Is Calculated
Lean body mass is your total body weight minus body fat: muscle, bone, organs, and water. It’s a useful baseline for tracking strength and metabolic changes over time, and it’s the input several other calculators on this site build on, most directly the Katch-McArdle path in the TDEE Calculator.
What This Calculator Measures
This estimates lean mass from height and weight alone, without requiring a body fat measurement. If you already know your body fat percentage, that’s a more direct route to the same number, since lean mass is simply your weight times one minus your body fat fraction.
The Formula
This calculator uses the Boer formula¹, developed from a Dutch adult sample and still one of the most widely used height-weight equations for lean mass in clinical settings.
Men: LBM = 0.407 × weight (kg) + 0.267 × height (cm) − 19.2
Women: LBM = 0.252 × weight (kg) + 0.473 × height (cm) − 48.3
How This Calculator Computes Your Result
Enter your sex, height, and weight above. We run the Boer formula directly and also report estimated fat mass as the remainder of your total body weight.
How Boer Compares to Other Formulas
Boer isn’t the only height-weight equation for lean mass. An earlier formula developed from a British sample² tends to produce noticeably lower estimates at typical modern body weights, since it was derived from a smaller, older population.
A more recent equation built from a much larger dataset spanning normal-weight through severely obese adults³ explicitly accounts for the fact that, at very high body weights, additional weight is overwhelmingly fat rather than lean tissue, something the older linear formulas don’t capture. For most people at a typical body weight, the different formulas agree within a few percent of each other, but they diverge more at the extremes.
Why It Matters
Two people can weigh the same yet have very different body composition. Tracking lean mass alongside weight shows whether changes come from muscle or fat. This is a formula-based estimate, and DEXA scans or BIA scales are more precise.
A Note on Accuracy
Boer formula estimates can vary from direct measurement methods by a few kilograms, and different height-weight formulas can disagree with each other, particularly at low or high body weights. Use it to track relative change over weeks, not as a precise clinical value.
Frequently Asked Questions
What is lean body mass?
Lean body mass is your total body weight minus fat mass. It includes muscle, bone, organs, and water, giving a picture of everything that isn't fat.
Which formula does this calculator use?
The Boer formula¹, a well-established equation for estimating lean body mass from height and weight.
Why do different LBM formulas give different results?
Each was built from a different study population using different methods¹,²,³. They tend to agree closely at typical body weights and diverge more at the extremes of height or weight.
Why track lean body mass instead of just weight?
Total weight doesn't distinguish between muscle and fat, so tracking lean mass helps confirm whether weight changes are coming from fat loss or gain versus muscle loss or gain.
Sources
Estimated Lean Body Mass as an Index for Normalization of Body Fluid Volumes in Humans, Boer, 1984
Prediction of Lean Body Mass from Height and Weight, Hume, 1966
Quantification of Lean Bodyweight, Janmahasatian et al., 2005