BMR Calculator
Find the calories your body burns at complete rest using the Mifflin-St Jeor equation.
Your TDEE estimates by activity level:
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What BMR Means
Basal metabolic rate is the energy your body uses to stay alive at complete rest. It covers breathing, heartbeat, maintaining body temperature, cell repair, and the ongoing activity of your organs. For most people BMR accounts for roughly 60 to 70 percent of total daily energy expenditure, which makes it the largest single component of the calories you burn.
The Mifflin-St Jeor Formula
This calculator uses the Mifflin-St Jeor equation, which is currently among the most accurate general-population formulas for estimating BMR.
- Men: BMR = (10 × weight in kg) + (6.25 × height in cm) − (5 × age) + 5
- Women: BMR = (10 × weight in kg) + (6.25 × height in cm) − (5 × age) − 161
The difference between the sexes reflects average differences in body composition rather than a judgement about individuals.
What Increases or Decreases BMR
- Body size: larger bodies burn more at rest.
- Muscle mass: muscle is more metabolically active than fat, so higher lean mass raises BMR.
- Age: BMR gradually declines, largely because lean mass tends to fall.
- Hormones: thyroid function in particular affects metabolic rate.
- Energy intake: prolonged severe restriction can lower BMR as the body adapts.
BMR Is Not Your Daily Calorie Need
BMR is the floor, not the total. Once you add movement, exercise, and the energy used to digest food, you arrive at total daily energy expenditure, or TDEE. The table above shows what your BMR becomes at each activity level. If you want to work from a single activity setting rather than a table, our TDEE Calculator does that.