What Is TDEE?
Total Daily Energy Expenditure (TDEE) is the total number of calories you burn in a day, combining your basal metabolic rate with the energy used through physical activity, digestion, and non-exercise movement. Knowing your TDEE is the foundation for any nutrition plan — whether your goal is to lose fat, build muscle, or maintain your current weight. Eating above your TDEE leads to weight gain, eating below leads to weight loss, and matching it maintains your weight.
The Mifflin-St Jeor Equation
This calculator uses the Mifflin-St Jeor equation, which is widely considered the most accurate BMR formula for the general population. Published in 1990, it replaced the older Harris-Benedict equation and has been validated in numerous studies. The formula calculates BMR from your weight, height, age, and gender, then multiplies by an activity factor to estimate your total daily calorie needs.
For men: BMR = 10 × weight(kg) + 6.25 × height(cm) − 5 × age(years) + 5. For women: BMR = 10 × weight(kg) + 6.25 × height(cm) − 5 × age(years) − 161.
Understanding Activity Levels
The activity multiplier is the most subjective part of the TDEE calculation. It ranges from 1.2 (sedentary) to 1.9 (extra active). A sedentary person doing no deliberate exercise burns roughly 20% more than their BMR through daily tasks. An athlete training twice daily with a physical job can burn nearly double their BMR. Most people overestimate their activity level — if you are unsure, start with "Lightly Active" or "Moderately Active" and adjust based on how your weight changes over 2-3 weeks.
How to Use TDEE for Your Goals
For fat loss, subtract 300-500 calories from your TDEE. This creates a moderate caloric deficit that preserves muscle mass while steadily reducing body fat. For muscle gain, add 200-400 calories above your TDEE to provide the surplus needed for muscle growth without excessive fat gain. For maintenance, aim to match your TDEE closely. In all cases, prioritize protein intake (0.7-1g per pound of body weight) and adjust your plan every few weeks based on how your body responds.
Frequently Asked Questions
What is the difference between BMR and TDEE?
- BMR (Basal Metabolic Rate) is the number of calories your body burns at complete rest just to keep you alive — breathing, circulation, cell production. TDEE (Total Daily Energy Expenditure) is your BMR multiplied by an activity factor that accounts for exercise and daily movement. TDEE is the number you should use for diet planning.
How accurate is the Mifflin-St Jeor equation?
- The Mifflin-St Jeor equation is considered the most accurate predictive BMR formula for most people, coming within 10% of measured values in research studies. However, individual variation exists — factors like muscle mass, genetics, and metabolic adaptation can cause your actual TDEE to differ. Use the result as a starting point and adjust based on real-world results over 2-4 weeks.
Which activity level should I choose?
- Be honest about your average week. Sedentary covers desk jobs with little exercise. Lightly Active covers 1-3 light workouts per week. Moderately Active is 3-5 days of moderate exercise. Very Active is hard training 6-7 days. Extra Active is for athletes training multiple times per day or those with physically demanding jobs. Most recreational lifters fall into the Moderately Active category.
How do I use TDEE to lose weight?
- To lose weight, eat fewer calories than your TDEE — typically 300-500 calories below for a sustainable deficit of about 0.5-1 lb per week. Cutting too aggressively (more than 1,000 below TDEE) can lead to muscle loss, fatigue, and metabolic slowdown. Track your weight weekly and adjust intake if progress stalls.
How often should I recalculate my TDEE?
- Recalculate whenever your weight changes by more than 10 lbs (4.5 kg), your activity level changes significantly, or every 3-6 months during a diet phase. As you lose weight, your TDEE decreases because your body requires less energy to maintain a smaller frame.