BMR Calculator
Calculate your Basal Metabolic Rate and Total Daily Energy Expenditure based on your age, gender, height, weight, and activity level.
Results
Mifflin-St Jeor BMR
calories/day
Harris-Benedict BMR
calories/day
Daily Calorie Needs (TDEE)
Based on Mifflin-St Jeor BMR. Your selected activity level is highlighted.
| Activity Level | Calories/day |
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These are population-level estimates. Individual metabolism varies with genetics, hormones, and body composition. Use these values as a starting point and adjust based on real-world results over time.
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BMR Calculator Formula
Mifflin-St Jeor (male):
BMR = (10 × kg) + (6.25 × cm) − (5 × age) + 5
kg = weight in kilograms, cm = height in centimeters, age = age in years
Mifflin-St Jeor (female):
BMR = (10 × kg) + (6.25 × cm) − (5 × age) − 161
Same formula with a sex constant: +5 for male, −161 for female.
How to Use This Calculator
- Choose your unit system: Imperial (feet, inches, pounds) or Metric (centimeters, kilograms).
- Select your gender and enter your age in years.
- Enter your height and weight in the fields that appear.
- Choose your activity level from the dropdown.
- Click Calculate BMR to see your Basal Metabolic Rate and daily calorie needs.
Frequently Asked Questions
What is BMR?
Basal Metabolic Rate (BMR) is the number of calories your body burns at complete rest to sustain basic functions such as breathing, circulation, and cell production. It accounts for roughly 60–70% of total daily energy expenditure for most people.
What is TDEE?
Total Daily Energy Expenditure (TDEE) is your BMR multiplied by an activity factor. It estimates the total calories you burn per day including exercise and movement. Eating at your TDEE maintains your current weight; eating below it creates a calorie deficit for weight loss. To check whether your current weight is in a healthy range, use our BMI calculator.
Which formula is more accurate?
The Mifflin-St Jeor equation is widely regarded as the most accurate for most people and is recommended by the Academy of Nutrition and Dietetics. The Harris-Benedict equation is an older formula that produces similar results. Both are shown for comparison.
Why do men and women have different BMR values?
Men typically carry more lean muscle mass than women at the same height and weight, and muscle tissue burns more calories at rest than fat. The Mifflin-St Jeor formula accounts for this with a sex-specific constant: +5 for men and −161 for women, a difference of 166 calories per day.
How accurate is my BMR result?
BMR formulas are population-level estimates with an individual error margin of roughly ±10%. Actual metabolic rate varies with genetics, hormones, body composition, and health status. Use these results as a starting point and adjust based on real-world outcomes over time.
Does BMR change with age?
Yes. BMR typically decreases with age due to loss of lean muscle mass and hormonal changes. The Mifflin-St Jeor formula accounts for this by subtracting 5 calories per year of age from the result.