Quick Calculators

BMR Calculator

Calculate your Basal Metabolic Rate (BMR) to discover exactly how many calories your body burns while completely at rest.

Basal Metabolic Rate

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Calories / Day

This is the minimum number of calories your body needs to perform basic life-sustaining functions (like breathing and circulation) if you were to sleep all day.

BMR vs. TDEE

Your Basal Metabolic Rate (BMR) is not the total number of calories you should eat in a day. It is strictly what you burn at rest.

To find how many calories you actually need to eat to maintain your weight, you must multiply your BMR by an activity multiplier. This new number is called your Total Daily Energy Expenditure (TDEE). If you want to calculate your TDEE, use our TDEE Calculator instead.

Last updated: July 2026

The BMR Formula

This calculator uses the Mifflin-St Jeor equation, widely considered the most accurate widely-used formula for estimating BMR from basic body measurements:

  • 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

Worked Example

Take a 30-year-old man who is 5'10" (177.8 cm) and weighs 160 lbs (about 72.6 kg):

BMR = (10 × 72.6) + (6.25 × 177.8) − (5 × 30) + 5 ≈ 1,692 calories/day

That's the estimated number of calories his body burns in 24 hours at complete rest. To find his actual daily calorie needs, he'd multiply this BMR by an activity multiplier using our TDEE Calculator.

This calculator provides an estimate based on population averages and is not a substitute for personalized medical or nutritional advice. Talk to a doctor or registered dietitian before making significant changes to your calorie intake.

Frequently Asked Questions

BMR (Basal Metabolic Rate) is the number of calories your body needs to perform basic life-sustaining functions, like breathing, circulation, and cell production, if you were at complete rest for 24 hours.
BMR only covers calories burned at rest. TDEE (Total Daily Energy Expenditure) adds in the calories burned through daily movement, exercise, and digestion. TDEE is always higher than BMR and is the number you should use to set calorie targets for weight loss or gain.
Mifflin-St Jeor is widely regarded as one of the most accurate predictive equations for estimating BMR in the general population, and is the formula used by most dietitians. It's still an estimate — actual BMR varies with muscle mass, genetics, and hormones.
No. Eating at or below your BMR for extended periods isn't recommended without medical supervision, since it can lead to muscle loss and a slowed metabolism. Your calorie target for weight loss should be based on your TDEE, not your BMR.
Yes. Muscle tissue burns more calories at rest than fat tissue, so two people with the same height, weight, and age can have different actual BMRs depending on body composition. This calculator doesn't account for body fat percentage directly.
The Mifflin-St Jeor equation adjusts for the average differences in body composition and metabolic rate between men and women, which is why the male formula adds 5 and the female formula subtracts 161.
Yes, BMR tends to decline gradually with age, largely due to natural loss of muscle mass over time. The formula accounts for this by subtracting a small amount for each year of age.