RMR Calculator
A 30-year-old man weighing 70 kg (154 lb) at 175 cm has an estimated RMR of about 1,696 calories a day. This RMR calculator uses the Revised Harris-Benedict equation to estimate resting metabolic rate from age, sex, height, and weight.
Quick answer
RMR estimates how many calories your body uses at rest in ordinary waking conditions.
What this tells you
- •RMR estimates how many calories your body uses at rest in ordinary waking conditions.
- •BMR is a stricter baseline measured under tighter lab-style conditions, so it is often a little lower than RMR.
- •This result is a planning estimate, not a diagnosis or metabolic test.
How to Use
- 1Enter sex, age, weight, and height.
- 2Use current measurements in kilograms and centimeters.
- 3Calculate to see estimated resting calories per day.
- 4Use the number as a starting point before activity, diet, or clinical adjustments.
How It Works
Formula
Male: RMR = 88.362 + 13.397W + 4.799H - 5.677A
Female: RMR = 447.593 + 9.247W + 3.098H - 4.330AThis tool uses the Revised Harris-Benedict equation. W is weight in kilograms, H is height in centimeters, and A is age in years. The estimate assumes adult inputs, stable body weight, and normal resting conditions rather than the stricter test setup used for true BMR measurement.
Calculation note: values are processed in the order shown above, using the current input units.
Worked Examples
Estimated RMR for a 30-year-old man
This is the estimated energy the body uses at rest before daily movement and exercise are added.
Estimated RMR for a 32-year-old woman
Two adults can have different RMR values because body size, age, and sex all affect the equation.
Common mistakes
- Treating RMR as the same as total daily calorie needs
- Using old body measurements after recent weight change
- Assuming the estimate reflects muscle mass, thyroid status, or medical conditions
Limitations
This equation uses population averages and sex-specific coefficients. It does not measure metabolism directly and does not account for body composition, recent exercise, illness, pregnancy, menopause, medications, thyroid conditions, or clinical indirect calorimetry.