# BMR calculator

Estimate how much energy your body uses at rest

Use it at https://www.quicktoolz.com/tools/bmr-calculator. From QuickToolz.

BMR stands for basal metabolic rate, the energy your body uses at rest in a day. We use the Mifflin-St Jeor equation, which is based on your weight, height, age and sex at birth. A 30-year-old woman who is 165 cm and 60 kg has a BMR of about 1,320 kcal.

## How it works

BMR = 10 × kg + 6.25 × cm − 5 × age + 5 (male) or − 161 (female)

The equation was published in 1990 and is widely used for adults. It uses sex at birth because it was built from measurements grouped that way.

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Worked example: For a 30-year-old woman, 165 cm and 60 kg: 600 + 1,031.25 − 150 − 161 = 1,320.25 kcal a day.

## Examples

| Age | Sex at birth | Height | Weight | BMR |
| --- | --- | --- | --- | --- |
| 25 | female | 160 cm | 55 kg | 1,264 kcal |
| 30 | female | 165 cm | 60 kg | 1,320 kcal |
| 30 | male | 180 cm | 80 kg | 1,780 kcal |
| 50 | male | 170 cm | 75 kg | 1,568 kcal |

## What this tool doesn't cover

- This is an estimate for adults. It isn’t for children, or during pregnancy.
- It doesn’t measure muscle or body fat. This isn’t medical advice.

## Questions

### What is the difference between BMR and calories?

BMR is energy at rest. Your daily calorie need adds your activity on top.

### How accurate is it?

It’s a good estimate for many adults, but people can differ from it. Treat it as a starting point.

### Why does it ask for sex at birth?

The formula was built from measurements grouped that way, so the numbers depend on it.

### What does BMR mean?

BMR is basal metabolic rate. It’s the energy your body uses at complete rest, to keep your heart, lungs and other organs working.

### Which BMR formula does this use?

It uses the Mifflin-St Jeor equation, which studies have found to be among the more accurate for most adults. It’s still an estimate.

## Sources

- [Mifflin et al. (1990), American Journal of Clinical Nutrition](https://doi.org/10.1093/ajcn/51.2.241)