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Basal Metabolic Rate Calculator

Compare basal metabolic rate estimates using the Mifflin–St Jeor and Revised Harris–Benedict equations.

Your measurements

These published equations use sex-specific constants.
In imperial mode, enter total inches (for example 69).

Your measurements stay in this browser. Results are informational estimates, not medical advice.

Estimated result
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Enter measurements to compare formulas
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How to use the BMR calculator

Enter consistent measurements to compare the published estimates.

1

Enter measurements

Select sex and units, then enter age, weight and height.

2

Calculate

The calculator applies both supported BMR equations.

3

Interpret carefully

BMR is resting energy expenditure and is not the same as total daily calorie needs.

Frequently Asked Questions

What is basal metabolic rate (BMR)?

Basal metabolic rate is an estimate of the energy your body needs to maintain essential functions, such as breathing and circulation, while at complete rest.

How does this BMR calculator work?

It uses your age, sex, weight and height to calculate estimates with the Mifflin–St Jeor and Revised Harris–Benedict equations. Comparing both can provide a useful starting range.

Why are there two BMR results?

The two results come from different published equations. They use similar inputs but different formulae, so modest differences are normal; neither result is an exact measurement.

Is BMR the same as my daily calorie requirement?

No. BMR covers energy used at rest. Your total daily energy expenditure also includes movement, exercise and the energy used to digest food, so it is usually higher than BMR.

How can I use my BMR to estimate daily calories?

Use your BMR as a starting point and apply an activity estimate to approximate total daily energy expenditure. Track your weight, energy levels and progress over time, then adjust as needed.

How accurate is a BMR calculation?

Formula-based BMR results are population estimates, not a direct measurement. Body composition, health conditions, medicines and day-to-day changes can all affect actual energy needs.

Should I use this calculator for a medical diet plan?

This calculator is for general informational use. If you are pregnant, under 18, have a medical condition, an eating disorder or specialised nutritional needs, seek advice from a qualified healthcare professional or registered dietitian.