BMR Calculator

What is BMR (Basal Metabolic Rate)?

Basal Metabolic Rate (BMR) is the number of calories your body needs to perform basic life-sustaining functions such as breathing, circulation, cell production and nutrient processing while at complete rest. It represents the minimum amount of energy your body requires to keep functioning if you were to stay in bed all day without any physical activity.

The Mifflin-St Jeor Equation

This calculator uses the Mifflin-St Jeor equation, which is considered the most accurate formula for estimating BMR by the American Dietetic Association. The formulas are:

For Men: BMR = (10 x weight in kg) + (6.25 x height in cm) - (5 x age in years) + 5

For Women: BMR = (10 x weight in kg) + (6.25 x height in cm) - (5 x age in years) - 161

For example, a 30-year-old male weighing 75 kg and 175 cm tall would have a BMR of (10 x 75) + (6.25 x 175) - (5 x 30) + 5 = 750 + 1093.75 - 150 + 5 = 1698.75 calories per day.

BMR vs TDEE: What is the Difference?

BMR only accounts for the energy needed at rest. Total Daily Energy Expenditure (TDEE) includes BMR plus the calories burned through daily activities and exercise. TDEE is calculated by multiplying your BMR by an activity factor. If you want to maintain your current weight, you should consume calories equal to your TDEE. For weight loss, eat fewer calories than your TDEE; for weight gain, eat more.

Activity Levels Explained

Sedentary (1.2): Little or no exercise, desk job.

Lightly Active (1.375): Light exercise or sports 1-3 days per week.

Moderately Active (1.55): Moderate exercise or sports 3-5 days per week.

Active (1.725): Hard exercise or sports 6-7 days per week.

Very Active (1.9): Very hard exercise, physical job, or training twice a day.

Frequently Asked Questions

How can I use BMR for weight loss?

To lose weight, you need to create a calorie deficit. A safe and sustainable approach is to consume about 500 calories less than your TDEE, which leads to approximately 0.5 kg of weight loss per week. Never eat below your BMR, as this can slow your metabolism and cause nutritional deficiencies.

Does BMR change with age?

Yes, BMR generally decreases with age. This is primarily due to loss of muscle mass and hormonal changes. This is why maintaining an active lifestyle and strength training becomes increasingly important as you age.

Is BMR the same for men and women?

No, men typically have a higher BMR than women because they generally have more muscle mass. The Mifflin-St Jeor equation accounts for this difference with separate formulas for each gender.