Resting Metabolic Rate (RMR) Calculator

RMR formulas

The resting metabolic rate (RMR), also known as basal metabolic rate (BMR) represents the amount of energy expended daily by the body when resting (or when sleeping), so to keep vital functions such as respiration or heart beating but with no additional activity.

The formulas used in the calculator above, depend on whether the data is input in the Metric or English system, and are the Harris-Benedict equations for basal metabolic rate:

RMR English Units

RMR Female = 655 + (4.35 x Weight lbs) + (4.7 x Height in) - (4.7 x Age yrs)

RMR Male = 66 + (6.23 x Weight lbs) + (12.7 x Height in) - (6.8 x Age yrs)

RMR Metric Units

RMR Female = 655 + (9.6 x Weight kg) + (1.8 x Height cm) - (4.7 x Age yrs)

RMR Male = 66 + (13.7 x Weight kg) + (5 x Height cm) - (6.8 x Age yrs)

RMR and weight loss or weight gain

If you wish to lose weight in a healthy way, you may want to consider a daily caloric intake that is between the RMR and RMR x 1.5 and to accompany your diet with suitable exercise and lifestyle changes. If you further eliminate 500kcal per day from your RMR, then you would be losing between 1 and 1.5 pounds per week – which is considered a generally accepted rate of health loss.

If you wish to gain weight, then you must consider a daily caloric intake that exceeds the RMR and is also adapted to the caloric consumption from your level of daily activity.

Factors that affect the RMR include subjects age (peaks in infancy then decreases with age), weight (distribution of lean muscle mass and fat mass), gender (females tend to have less lean mass so lower RMRs) and body surface.

References

Harris J, Benedict F. A Biometric Study of Human Basal Metabolism. PNAS. 1918; 4 (12): 370–3.

Müller B, Merk S, Bürgi U, Diem P. Calculating the basal metabolic rate and severe and morbid obesity Praxis (Bern 1994) 2001; 90 (45): 1955–63.