BMR & TDEE Calculator
Calculate your Basal Metabolic Rate (BMR) and Total Daily Energy Expenditure (TDEE) using the Mifflin-St Jeor equation. Find your daily calorie needs by activity level.
What Is the BMR & TDEE Calculator?
The Basal Metabolic Rate (BMR) is the number of calories your body burns at complete rest to maintain basic life functions — breathing, circulation, and cell production. The Total Daily Energy Expenditure (TDEE) multiplies BMR by an activity factor to estimate your actual daily calorie needs. This calculator uses the Mifflin-St Jeor equation, which is considered the most accurate formula for the general population.
Formula
How to Use
Enter your weight, height, age, and sex. Select your typical activity level. The calculator instantly shows your BMR and TDEE. BMR is your minimum calorie floor; your TDEE is what you need to maintain your current weight. To lose weight, consume less than your TDEE; to gain, consume more.
Example Calculation
A 30-year-old woman, 165 cm tall, 65 kg, moderately active: BMR = 10×65 + 6.25×165 − 5×30 − 161 = 1,421 kcal/day. With moderate activity (×1.55): TDEE ≈ 2,202 kcal/day.
Understanding BMR & TDEE
The Mifflin-St Jeor equation, published in 1990, is the gold standard for estimating resting energy expenditure. Unlike the older Harris-Benedict equation (1919), it was derived from a more representative modern population and accounts more accurately for the lower metabolic rates typical of sedentary lifestyles.
BMR represents the energy cost of keeping your heart beating, lungs breathing, brain functioning, and temperature regulated — with no movement at all. It accounts for roughly 60–70% of total daily calorie expenditure for most people.
The TDEE activity multipliers are: Sedentary ×1.2, Lightly Active ×1.375, Moderately Active ×1.55, Very Active ×1.725, Extra Active ×1.9. These are population averages; individual variation is significant.
Knowing your TDEE is essential for calorie-based nutrition planning, whether your goal is fat loss, muscle gain, or weight maintenance. Sports dietitians use BMR and TDEE as the foundation of personalised nutrition prescriptions.
Frequently Asked Questions
What is the difference between BMR and TDEE?
BMR (Basal Metabolic Rate) is the energy your body needs at complete rest — just to stay alive. TDEE (Total Daily Energy Expenditure) adds the calories you burn through daily activity and exercise on top of BMR.
Which BMR formula does this use?
This calculator uses the Mifflin-St Jeor equation (1990), which is the most widely validated formula for the general population and recommended by dietitians over the older Harris-Benedict equation.
How accurate is the BMR calculation?
The Mifflin-St Jeor equation is accurate within ±10% for most people. Athletes with high muscle mass may have a higher actual BMR than calculated, since muscle burns more calories than fat at rest.
What activity level should I choose?
Choose Sedentary for desk jobs with little exercise; Lightly Active for 1–3 days of exercise per week; Moderately Active for 3–5 days; Very Active for 6–7 days of hard exercise; Extra Active for physical jobs plus daily exercise.
Can I use this for weight loss planning?
Yes. Your TDEE is your maintenance calorie level. A deficit of 500 kcal/day below TDEE typically yields about 0.5 kg (1 lb) of weight loss per week. Do not eat below your BMR without medical supervision.