What is BMR and TDEE?

BMR (Basal Metabolic Rate) is the number of calories your body burns at rest just to keep you alive (breathing, circulating blood, cellular growth). TDEE (Total Daily Energy Expenditure) is an estimate of how many calories you burn per day when exercise and daily activity are taken into account.

How Does the BMR Calculator Work?

Our calculator uses your age, gender, height, and weight to determine your base BMR using the Mifflin-St Jeor equation. It then applies an activity multiplier based on how active you are during the week to calculate your true Maintenance Calories (TDEE). From there, we provide safe caloric targets for weight loss or weight gain.

The Mifflin-St Jeor Equation

The core engine behind this calculator relies on the Mifflin-St Jeor Equation, which is currently considered the most accurate formula by the American Dietetic Association. The formula is:

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

TDEE = BMR × Activity Multiplier

Practical Example

Let's assume you are a 30-year-old male, weighing 75 kg, and 175 cm tall, who works out 3-5 days a week (Moderate Activity multiplier of 1.55).

Step 1: Calculate BMR: (10 × 75) + (6.25 × 175) - (5 × 30) + 5 = 1,699 calories
Step 2: Calculate TDEE: 1,699 × 1.55 = 2,633 calories

If this person wants to lose 1 pound per week (a 500-calorie daily deficit), their target calorie intake would be 2,133 calories/day.

Major Benefits of Calculating Your BMR

Precision Dieting: Stop guessing how much you should eat. TDEE gives you an exact mathematical baseline for your diet.
Safe Weight Loss: Ensure you are not dropping your calories dangerously low (below your BMR), which can crash your metabolism.
Muscle Gain: To build muscle, you need to be in a caloric surplus. Knowing your TDEE ensures you eat enough to grow without gaining excessive fat.