BMR Calculator

Your Basal Metabolic Rate (BMR) is the total number of calories your body requires to perform its most basic, life-sustaining functions—such as breathing, circulation, nutrient processing, and cell production—while completely at rest. Whether your goal is to lose weight, gain muscle, or maintain your current physique, understanding your BMR is the crucial first step in any structured nutrition plan.

How is BMR Calculated? (Mifflin-St Jeor Equation)

Historically, the Harris-Benedict equation was the standard for calculating BMR. However, modern dietetics and the American Dietetic Association now widely recommend the Mifflin-St Jeor Equation, as studies show it is significantly more accurate for calculating resting metabolism.

Formula for Men:

BMR = (10 × weight in kg) + (6.25 × height in cm) - (5 × age in years) + 5

Formula for Women:

BMR = (10 × weight in kg) + (6.25 × height in cm) - (5 × age in years) - 161

Example of BMR Calculation

Let’s calculate the BMR for a 30-year-old Indian woman who weighs 65 kg and is 160 cm (approx 5'3") tall.

Weight factor: 10 × 65 = 650
Height factor: 6.25 × 160 = 1,000
Age factor: 5 × 30 = 150
Calculation: 650 + 1,000 - 150 - 161 = 1,339 kcal/day

This means if she were to lay in bed all day without moving, her body would naturally burn 1,339 calories just to stay alive.

Difference Between BMR and TDEE

It is extremely important to note that BMR is not the total number of calories you burn in a day. To find your Total Daily Energy Expenditure (TDEE), you must multiply your BMR by an activity multiplier (ranging from 1.2 for sedentary lifestyles to 1.9 for professional athletes). Eating below your BMR for extended periods is medically dangerous and can cause severe metabolic adaptation.