# RMR Calculator (Resting Metabolic Rate)

URL: https://speedycalculator.com/calculators/health/rmr/
Last updated: 2026-10-30

> The RMR calculator estimates your resting metabolic rate – the calories you burn while resting quietly – with the Mifflin–St Jeor equation, and shows how it splits per hour and per kilogram of body weight.

## Inputs

- Sex
- Age (years)
- Weight (kg, lb, st, g)
- Height (cm, in, m, ft, mm)
- Measured RMR (optional) (kcal/day)

## Results

- Predicted RMR
- Calories per hour at rest
- Calories per kg
- Measured vs predicted

## Formula

```
RMR (Mifflin–St Jeor) = 10W + 6.25H − 5A + 5 (men) or − 161 (women)
RMR per kg = RMR ÷ weight
```

## Explanation

Resting metabolic rate is measured after a short rest rather than the strict overnight fast needed for BMR, so it is slightly higher but much easier to measure. The Mifflin–St Jeor equation was actually derived from RMR measurements.

### How to use the RMR Calculator

- **Sex**
- **Age**
- **Weight**
- **Height**
- **Measured RMR (optional)**

Results update as you type, and every field accepts the units shown in its menu.

### How it works

Enter sex, age, weight and height. If you have had your RMR measured with indirect calorimetry, compare it with the prediction to see if your metabolism is faster or slower than average.

### Inputs explained

FieldWhat to enterSexChoose one: Male, FemaleAgeIn yearsWeightUnits: kg, lb, st, gHeightUnits: cm, in, m, ft, mmMeasured RMR (optional)In kcal/day

### What each result means

- **Calories per hour at rest** = [Predicted RMR]÷24
- **Calories per kg** = [Predicted RMR]÷[Weight]

### Example values

How the main result changes when **Age** changes and everything else stays at the example values above:

Age (years)Predicted RMR (kcal/day)151,79322.51,755301,71837.51,680451,643601,568
*Health note: this calculator is for education and screening only and is not a diagnosis or treatment advice. Discuss your results with a qualified clinician.*

## Worked example

Inputs — Sex: Male; Age: 30 years; Weight: 75 kg; Height: 178 cm; Measured RMR (optional): 0 kcal/day.

Results — **Predicted RMR = 1,718 kcal/day**; Calories per hour at rest = 71.6 kcal/h; Calories per kg = 22.9 kcal/kg/day; Measured vs predicted = 0 %.

## Key terms

- **RMR**: Resting metabolic rate.

## FAQ

**What is the difference between RMR and BMR?**
RMR is measured under less strict conditions and is typically up to 10% higher.

**How is RMR measured?**
With indirect calorimetry, which measures oxygen used and carbon dioxide breathed out.

**Is a low RMR a problem?**
Large drops after dieting or illness are worth discussing with a doctor.


## Sources

- [Mifflin MD et al. A new predictive equation for resting energy expenditure in healthy individuals. Am J Clin Nutr, 1990](https://pubmed.ncbi.nlm.nih.gov/2305711/)
- [Roza AM, Shizgal HM. The Harris Benedict equation reevaluated. Am J Clin Nutr, 1984](https://pubmed.ncbi.nlm.nih.gov/6741850/)
- McArdle WD, Katch FI, Katch VL. Exercise Physiology: Nutrition, Energy and Human Performance