Calculate your Total Daily Energy Expenditure (TDEE) and daily calorie needs using the Mifflin-St Jeor BMR formula.
How BMR and TDEE Are Calculated
This calculator uses the Mifflin-St Jeor equation, widely regarded as the most accurate BMR formula for most adults, to estimate your Basal Metabolic Rate (BMR) — the calories your body burns at complete rest just to maintain basic functions. It then multiplies BMR by an activity factor to produce Total Daily Energy Expenditure (TDEE), your estimated maintenance calorie intake including movement and exercise.
Choosing the Right Activity Level
The activity multiplier ranges from 1.2 for a sedentary lifestyle (little to no exercise, desk job) up to 1.9 for a very active lifestyle (hard daily exercise or a physical job plus training). Selecting a level higher than your actual activity overstates your calorie needs and can stall weight-loss goals, so pick the option that matches your typical week, not your best week.
Using TDEE for Weight Goals
Eating at your TDEE maintains current weight. A deficit of roughly 500 kcal/day below TDEE produces about 0.5 kg of weight loss per week, while the same surplus produces roughly 0.5 kg of gain per week. These are estimates — actual results vary with individual metabolism, so adjust intake based on real-world progress over 2–3 weeks rather than the formula alone.
What is the Mifflin-St Jeor equation?
The Mifflin-St Jeor equation estimates Basal Metabolic Rate (BMR) from weight, height, age, and sex, and is widely regarded as the most accurate BMR formula for most adults.
Should I eat exactly my TDEE?
Eating at TDEE maintains current weight. A roughly 500 kcal/day deficit produces about 0.5 kg of weight loss per week, and the same surplus produces roughly 0.5 kg of gain per week.