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BMR Calculator

Calculate your Basal Metabolic Rate — the calories your body burns at rest — using the Mifflin-St Jeor or revised Harris-Benedict formula. Enter gender, age, height and weight for an instant result.

Basal Metabolic Rate — kcal/day

BMR is the calories your body burns at complete rest. Multiply by your activity level to estimate total daily needs.

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This page replaces the individual converters below, which remain available as standalone pages.

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What BMR means

Basal Metabolic Rate is the energy your body needs for basic functions — breathing, circulation, cell repair — at complete rest. It is the baseline for any calorie plan: multiply it by an activity factor to get your total daily energy expenditure (TDEE).

The two formulas

Mifflin-St Jeor (1990) is the most widely validated for modern populations. The revised Harris-Benedict (1984) is the classic clinical standard. Both need gender, age, height and weight; results usually differ by less than 5%.

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BMR Calculator FAQs

Which formula should I use?
Mifflin-St Jeor is generally preferred today and validated against more recent data. Harris-Benedict remains common in clinical settings. Try both and compare.
Does BMR include exercise?
No. BMR is rest only. For total daily calories, multiply your BMR by an activity factor (1.2 sedentary up to 1.9 very active).
Why do men and women get different results?
The formulas account for average differences in muscle mass and body composition between sexes at the same height and weight.
How accurate is this?
Within about 10% for most people. Muscle mass, hormones and medical conditions shift real BMR, so treat it as a starting estimate.
Is my data stored?
No. All calculation happens in your browser; nothing is sent or saved.
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