BMR Calculator & Equation
Calculate your Basal Metabolic Rate using the Mifflin-St Jeor Equation
Sedentary (little or no exercise)
Lightly Active (exercise 1-3 days/week)
Moderately Active (exercise 3-5 days/week)
Very Active (hard exercise 6-7 days/week)
Extra Active (very hard exercise/physical job)
Your Results
Basal Metabolic Rate (BMR):
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Daily Calories to Maintain Weight:
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*Based on the Mifflin-St Jeor equation. These are estimated caloric needs.
Understanding the Basal Metabolic Rate Equation
Your Basal Metabolic Rate (BMR) represents the number of calories your body requires to perform the most basic (basal) functions. Even when resting completely, your body burns calories to sustain breathing, blood circulation, cell production, and nutrient processing. In short, BMR is the energy cost of staying alive.
This calculator utilizes the Mifflin-St Jeor Equation, which is widely considered by clinical nutritionists to be the most accurate formula for estimating calorie needs in the general population. Knowing your BMR is the first critical step in designing a nutrition plan for weight loss, maintenance, or muscle gain.
The Formulas: How BMR is Calculated
While there are several formulas, the Mifflin-St Jeor equation is the standard. The logic differs slightly for men and women due to differences in lean body mass.
For Men:
BMR = (10 × weight in kg) + (6.25 × height in cm) - (5 × age in years) + 5
For Women:
BMR = (10 × weight in kg) + (6.25 × height in cm) - (5 × age in years) - 161
From BMR to TDEE
BMR only accounts for resting energy. To find your Total Daily Energy Expenditure (TDEE)—the actual amount of calories you burn in a day—you must multiply your BMR by an activity factor. This calculator handles that math for you automatically.
- Sedentary (BMR x 1.2): Desk job, little to no exercise.
- Lightly Active (BMR x 1.375): Light exercise or sports 1-3 days per week.
- Moderately Active (BMR x 1.55): Moderate exercise 3-5 days per week.
- Very Active (BMR x 1.725): Hard exercise 6-7 days per week.
- Extra Active (BMR x 1.9): Very hard exercise, physical job, or twice-daily training.
Using These Numbers for Weight Goals
Once you have your TDEE (Maintenance Calories), you can adjust your intake based on your goals:
- Weight Loss: Subtract 500 calories from your TDEE to lose roughly 0.5 kg (1 lb) per week.
- Weight Gain: Add 250-500 calories to your TDEE to support muscle growth.
- Maintenance: Eat roughly the TDEE amount to maintain your current weight.