What is the normal muscle mass range for adults based on age, height, and weight?

Normal Muscle Mass Ranges by Age, Height, and Weight

Use the National Kidney Foundation's mid-arm muscle circumference percentile tables as the primary clinical reference for assessing muscle mass in adults aged 18-74 years, stratified by sex, age, and height. 1

Reference Values for Adult Men

Mid-Arm Muscle Circumference (MAMC) by Age Group 1

• Ages 18-24 years: Mean 27.4 cm (5th percentile: 23.5 cm, 95th percentile: 32.3 cm)
• Ages 25-34 years: Mean 28.3 cm (5th percentile: 24.2 cm, 95th percentile: 32.9 cm)
• Ages 35-44 years: Mean 28.8 cm (5th percentile: 25.0 cm, 95th percentile: 33.0 cm)
• Ages 45-54 years: Mean 28.2 cm (5th percentile: 24.0 cm, 95th percentile: 32.6 cm)
• Ages 55-64 years: Mean 27.8 cm (5th percentile: 22.8 cm, 95th percentile: 31.8 cm)
• Ages 65-74 years: Mean 26.8 cm (5th percentile: 22.5 cm, 95th percentile: 30.7 cm)

Total Skeletal Muscle Mass Estimates 2

• Prediction equation: SM (kg) = 0.244 × body weight (kg) + 7.80 × height (m) + 6.6 - 0.098 × age + race adjustment
• Race adjustments: -1.2 kg for Asian, +1.4 kg for African American, 0 for White and Hispanic 2
• Expected range in healthy non-obese men: Median 31.2 kg, interquartile range 27.9-31.5 kg, with extremes from 21.1 kg to 40.2 kg 3

Muscle Mass as Percentage of Body Weight 3

• 25th percentile: 33.1% of body weight
• 50th percentile: 36.4% of body weight
• 75th percentile: 39.6% of body weight
• Athletes (body-builders): Up to 65.1% of body weight 4

Reference Values for Adult Women

Mid-Arm Muscle Circumference (MAMC) by Age Group 1

• Ages 18-24 years: Mean 20.9 cm (5th percentile: 17.7 cm, 95th percentile: 24.9 cm)
• Ages 25-34 years: Mean 21.7 cm (5th percentile: 18.3 cm, 95th percentile: 26.6 cm)
• Ages 35-44 years: Mean 22.5 cm (5th percentile: 18.5 cm, 95th percentile: 27.4 cm)
• Ages 45-54 years: Mean 22.7 cm (5th percentile: 18.8 cm, 95th percentile: 27.8 cm)
• Ages 55-64 years: Mean 22.8 cm (5th percentile: 18.6 cm, 95th percentile: 28.1 cm)
• Ages 65-74 years: Mean 22.8 cm (5th percentile: 18.6 cm, 95th percentile: 28.1 cm)

Total Skeletal Muscle Mass Estimates 2

• Prediction equation: SM (kg) = 0.244 × body weight (kg) + 7.80 × height (m) - 0.098 × age + race adjustment - 3.3
• Expected range in healthy non-obese women: Median 21.1 kg, interquartile range 18.8-21.4 kg, with extremes from 13.9 kg to 28.6 kg 3

Muscle Mass as Percentage of Body Weight 3

• 25th percentile: 24.2% of body weight
• 50th percentile: 27.5% of body weight
• 75th percentile: 30.8% of body weight

Age-Related Changes in Muscle Mass

Significant muscle mass decline begins after age 60, with the most pronounced losses occurring after age 80. 5

• Ages 60-69 vs. <70 years: Fat-free mass decreases by 4.2 kg (7.3%) in men and 2.9 kg (6.8%) in women 5
• Ages 80+ vs. 70-79 years: All lean body mass parameters show significant decline (P<0.05) 5
• Sarcopenia prevalence at age 60+: 45% of men and 30% of women by body cell mass index criteria; 11% of both sexes by relative skeletal muscle mass index 5

Clinical Application Algorithm

Step 1: Measure Mid-Arm Muscle Circumference 1

1. Measure mid-upper arm circumference at the midpoint between acromion and olecranon
2. Measure triceps skinfold thickness at the same location
3. Calculate MAMC = arm circumference (cm) - [π × triceps skinfold (cm)]
4. Compare to age- and sex-specific percentile tables

Step 2: Interpret Percentile Rankings 1

• Below 5th percentile: Severe muscle depletion requiring intervention
• 5th-25th percentile: Mild to moderate muscle depletion
• 25th-75th percentile: Normal muscle mass range
• Above 75th percentile: Above-average muscularity

Step 3: Consider Body Composition Context 3

• High muscularity (>75th percentile) associates with smaller waist circumference, less visceral fat, larger organ mass, and higher resting energy expenditure
• Low muscularity (<25th percentile) may indicate sarcopenia, malnutrition, or chronic disease even with normal BMI
• Muscle mass varies widely (interquartile range ~3-4 kg) among individuals of identical sex, age, weight, and height 3

Important Clinical Caveats

Dual-energy X-ray absorptiometry (DXA) may underestimate age-related muscle loss compared to urinary creatinine excretion, particularly in older adults. 6 Changes in body water content with aging contribute to this discrepancy, making DXA-based appendicular lean mass less sensitive for detecting sarcopenia than functional measures or creatinine excretion 6.

Energy intake must be considered when evaluating protein intake effects on muscle mass, as the relationship between dietary protein and muscle mass disappears when correcting for total energy intake in older adults 1. This emphasizes that adequate caloric intake is prerequisite for protein to support muscle maintenance.

Skeletal muscle comprises the largest body compartment in most adults without obesity, constituting the primary fraction of body weight up to BMI 35 kg/m² in men and 25 kg/m² in women 3. Beyond these BMI thresholds, adipose tissue becomes the dominant compartment.