Skeletal Muscle Mass Calculator
Use this skeletal muscle mass calculator to estimate your total muscle mass from height, weight, age, and sex.
Updated October 2, 2026
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 Skeletal Muscle Mass Is Calculated
Skeletal muscle mass is the total weight of the muscles attached to your skeleton, the muscle you can build and lose through training and diet, as opposed to organ tissue or other lean mass. This calculator estimates it from basic measurements using a published anthropometric prediction equation, without needing a DEXA or BIA scan.
What This Calculator Measures
This estimates total skeletal muscle mass in kg or lb, and what percentage of your total body weight that represents. It does not distinguish muscle mass by body region (arms versus legs, for example).
The Formula
This calculator uses the height, weight, age, and sex portion of a validated anthropometric prediction model¹:
Skeletal Muscle Mass (kg) = 0.244 x Weight (kg) + 7.80 x Height (m) - 0.098 x Age + 6.6 x Sex (1 for male, 0 for female) - 3.3
The original published equation also includes a race/ethnicity adjustment term. This calculator deliberately omits that term and uses height, weight, age, and sex only, the same direction recent kidney-function research has moved in by removing race coefficients from similar equations.
How This Calculator Computes Your Result
Enter your height, weight, age, and sex. We apply the formula above and return your estimated skeletal muscle mass in both kg and lb, along with that figure as a percentage of your total body weight.
Why This Equation Omits a Race Adjustment Term
The original research behind this equation found that average skeletal muscle mass, independent of height, weight, age, and sex, differed somewhat by the race categories used in the study sample¹. Using a race-based adjustment term in a biological formula has become a more actively debated methodological choice across medicine in recent years, most visibly in kidney function testing, where a similar coefficient was removed from the standard GFR equation in 2021 specifically because it risked encoding race as if it were a fixed biological category rather than a social one. This calculator follows that same reasoning and omits the term, which means results are based on the height, weight, age, and sex relationship alone.
Why Skeletal Muscle Mass Matters Beyond Appearance
Skeletal muscle mass naturally declines with age, a process that accelerates after roughly age 60 and is closely tied to strength, balance, and independence later in life. A 2019 European consensus defined sarcopenia, clinically significant age-related muscle loss, as a condition in its own right, distinct from simply getting older, precisely because low muscle mass is linked to falls, frailty, and reduced quality of life². Tracking skeletal muscle mass over time, not just at a single point, is one way to catch a declining trend early, well before it becomes a functional problem.
A Note on Accuracy
This is a predictive estimate from a population-level equation, not a direct measurement. The original validation study reported a standard error of about 2.8 kg on a sample of 244 healthy, non-obese adults, individual accuracy varies, and this equation has not been validated for children, pregnant individuals, or people at the extreme ends of the height or weight range. For a body mass index in the obese range, treat the result as a rougher estimate.
Frequently Asked Questions
How is skeletal muscle mass calculated without a scan?
Using a validated anthropometric equation based on height, weight, age, and sex, developed and cross-validated against actual muscle mass measurements in a research study¹.
Is this as accurate as a DEXA or BIA scan?
No. This is a population-level estimate with a margin of error of a few kilograms, a DEXA or BIA scan measures your actual body composition directly and will be more precise for any individual.
Why doesn't this calculator ask about race or ethnicity?
The original research equation included a race adjustment term, but this calculator omits it by deliberate choice, following the same reasoning that led researchers to remove a similar race coefficient from standard kidney function equations.
What's a healthy skeletal muscle mass percentage?
This varies by age, sex, and overall body composition goals, there isn't one universal healthy number. Track your own trend over time alongside strength and overall health markers rather than comparing to a single target figure.
Sources
Total-Body Skeletal Muscle Mass: Development and Cross-Validation of Anthropometric Prediction Models, Lee et al., American Journal of Clinical Nutrition, 2000
Sarcopenia: Revised European Consensus on Definition and Diagnosis, Cruz-Jentoft et al., Age and Ageing, 2019