CalcBrew

BMR Calculator

Calculate your basal metabolic rate (BMR) — energy burned at rest — with the Mifflin–St Jeor equation. To include daily activity, see the TDEE calculator.

By Miikka · CalcBrew · Updated

1,674 kcal

Basal metabolic rate

BMR (at rest)1,674 kcal
Light activity (×1.375)2,301 kcal
Moderate (×1.55)2,594 kcal
ℹ️ BMR is the energy your body uses at rest. Multiply by an activity factor for daily expenditure.
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A BMR calculator estimates how much energy your body burns at complete rest just to keep its basic functions running. It is the starting point for working out your daily calorie needs once you add your activity level.

How the calculator works and what it’s for▾

How BMR is calculated

The calculator uses the Mifflin–St Jeor equation, which takes sex, weight, height and age into account. This formula is widely recommended today because it gives realistic estimates.

BMR represents the energy your body spends at rest on breathing, circulation, producing heat and other essential functions.

What you enter and what you get

You enter your sex, weight in kilograms, height in centimetres and age in years. The calculator returns your resting expenditure plus two estimates for light and moderate activity.

The activity estimates multiply your BMR by 1.375 (light) and 1.55 (moderate), giving you an approximate daily energy expenditure.

What the number is used for

BMR is the foundation of weight management: once you know your resting burn and activity, you can estimate maintenance calories and adjust your eating to your goal.

To lose weight you aim below maintenance, and to build muscle above it. The baseline figure helps you set a realistic target.

Good to know

BMR is an estimate, not an exact measurement. Muscle mass, genetics and hormones affect actual expenditure, so individual differences are possible.

Use the number as a guideline and watch how your weight moves over a few weeks. Adjust your calories based on what you observe.

🔄 Reviewed June 2026

Frequently asked questions

Cite this calculator
APACalcBrew. (2026). BMR Calculator. https://calcbrew.com/bmr-calculator
MLA“BMR Calculator.” CalcBrew, 2026, calcbrew.com/bmr-calculator.

Link to https://calcbrew.com/bmr-calculator. Results are estimates; cite the underlying formula or data source for academic work.

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