Reference

Average BMR by age and sex

Estimated average basal metabolic rate for adult men and women in each age group, calculated with the Mifflin–St Jeor equation from national average height and weight data.

Average BMR for men

Mifflin–St Jeor at each group’s average height and weight, using the midpoint age of the group (85 for 80+). Body-size data: CDC/NCHS, NHANES August 2021–August 2023.

Average BMR for women

Mifflin–St Jeor at each group’s average height and weight, using the midpoint age of the group (85 for 80+). Body-size data: CDC/NCHS, NHANES August 2021–August 2023.

How to compare your own result

Calculate your estimate with the BMR calculator, then look at the row for your age and sex. The calculator also shows the matching average under your result.

• A result below the average is not “slow metabolism”. If you are shorter or lighter than the average person in the table, your estimate will be lower. That reflects body size, not a problem.
• A result above the average is not “fast metabolism”. A larger body uses more energy at rest.
• The equation cannot see muscle. Two people with the same height, weight and age get the same estimate, even though the one with more fat-free mass usually has a higher measured BMR.

Why average BMR falls with age

Most of the drop in the tables comes from the equation’s age term, which subtracts 5 kcal/day for each year, plus smaller average height and, after middle age, lower average weight. Research using measured energy expenditure found that, once body size and composition are accounted for, total and basal expenditure stayed broadly stable from about 20 to 60 years and declined in older age. See how to increase your BMR for what you can and cannot change.

How these averages were calculated

1. Average height and weight for each age group and sex were taken from the U.S. National Health and Nutrition Examination Survey (NHANES), August 2021–August 2023. The weight data exclude pregnant women.
2. Each group’s averages were entered into the Mifflin–St Jeor equation, the same primary equation the calculator uses.
3. Because the equation is linear, this gives the average predicted BMR for people of that age and sex, not a measured BMR.

Limits of these averages

• They describe the United States. Countries where average height and weight are different will have different averages. Use your own calculated result rather than the table for decisions.
• They are predictions. Mifflin–St Jeor estimates population averages; individual measured values can differ substantially.
• The 80+ row is outside the equation’s study range. Mifflin–St Jeor was developed in adults aged 19–78.
• Ages 18–19 are not covered. The national survey groups start at age 20.

Source

1. Fryar CD, Gu Q, Afful J, Carroll MD, Ogden CL. Anthropometric reference data for children and adults: United States, August 2021–August 2023. Vital Health Stat 3(50). National Center for Health Statistics; 2025. Tables 3 and 7. CDC Stacks (DOI 10.15620/cdc/174595).
2. Mifflin MD, St Jeor ST, et al. A new predictive equation for resting energy expenditure in healthy individuals. Am J Clin Nutr. 1990;51(2):241-247. PMID 2305711.
3. Pontzer H, Yamada Y, Sagayama H, et al. Daily energy expenditure through the human life course. Science. 2021;373(6556):808-812. PMID 34385400.