By Zencalcy Editorial TeamLast reviewed About us
Resting metabolic rate is the energy you use while awake, resting and not digesting a meal. It is closely related to basal metabolic rate, but measured under less strict conditions, so it usually comes out slightly higher. This calculator estimates RMR from sex, age, height and weight using the Mifflin-St Jeor equation.
Resting metabolic rate estimate with the Mifflin-St Jeor equation.
Men: RMR = 10w + 6.25h - 5a + 5 Women: RMR = 10w + 6.25h - 5a - 161
The Mifflin-St Jeor equation was developed to predict resting energy expenditure, which is why it is often labelled an RMR equation even when used as a BMR estimate. Strict BMR measurement requires an overnight fast, complete rest and a controlled environment, while RMR allows looser conditions.
| Symbol | Meaning |
|---|---|
| w | Body weight in kilograms. |
| h | Standing height in centimetres. |
| a | Age in years. |
| RMR | Resting metabolic rate in kilocalories per day. |
RMR = 10 x 60 + 6.25 x 165 - 5 x 30 - 161 = 600 + 1031.25 - 150 - 161 = 1320.25, which rounds to 1320.3 kcal per day. The same woman would have a slightly higher measured RMR if she were awake and had eaten recently.
The distinction between RMR and BMR matters most in a laboratory. BMR requires an overnight fast, a comfortable temperature and complete physical rest, often measured shortly after waking. RMR relaxes those conditions, so it captures the energy cost of being awake and having recently eaten or moved. Because RMR is easier to measure, many practitioners use it as the practical resting estimate. For everyday planning, the difference is small relative to the uncertainty in any prediction and the variability of daily activity. What matters more is consistency: use the same equation, add an activity factor that reflects your real week, and check the result against your weight trend. If your weight is stable on a given intake, that intake is your working maintenance value regardless of the label on the equation.
Continue with the BMR Calculator (Mifflin-St Jeor), Harris-Benedict Calculator, or the Katch-McArdle Calculator — or browse more dietary tools and all health calculators.
Also see the Calorie Calculator, TDEE Calculator and the Macro Calculator.
BMR is measured under strict basal conditions, usually after a fast and full rest. RMR is measured under more relaxed conditions, so it includes a small amount of recent activity and digestion. RMR is typically a few percent higher than BMR.
Energy and nutrient estimates are population guidance, not personal prescriptions. Actual needs vary with body composition, medical conditions, medication, pregnancy and activity. Values are rounded and should be discussed with a registered dietitian or clinician when used to plan treatment.
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Last reviewed: September 2026. See how we build and check every tool on the about page.
Content updated: September 2026