Basal metabolic rate is the number of calories your body burns at complete rest just to keep essential functions running — breathing, circulation, cell repair — before accounting for any movement or exercise. This calculator uses the Mifflin-St Jeor equation, a widely used and reasonably accurate formula, to estimate BMR from your age, gender, height, and weight.
Beyond the base number, it also multiplies your BMR by standard activity multipliers to estimate total daily calorie needs at different activity levels, from sedentary to very active, which is more directly useful for planning nutrition.
These figures are population-level estimates rather than a precise measurement of your individual metabolism, which can only really be determined through clinical testing, so treat the result as a reasonable starting point rather than an exact target.
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Frequently asked questions
What formula does this use?
The Mifflin-St Jeor equation, which is generally considered one of the more accurate widely available BMR formulas for the general population.
Should I eat exactly at my BMR to lose weight?
No, BMR represents calories burned at complete rest — actual weight management should be based on total daily energy expenditure, which includes activity, shown in the activity-level breakdown.