What Does TDEE Stand For?
TDEE stands for Total Daily Energy Expenditure, the total number of calories your body burns in a 24-hour period. It includes every calorie you use: the energy needed to keep your organs functioning at rest, the calories burned digesting food, and every bit of movement you make throughout the day.
Understanding your TDEE gives you a precise calorie target to work from. Eat less than your TDEE and you lose weight. Eat more and you gain. Eat exactly your TDEE and your weight stays stable. Without this number, you're guessing, and guessing is why most diets fail.
How Is TDEE Calculated?
TDEE is calculated in two steps. First, your Basal Metabolic Rate (BMR) is estimated, this is the number of calories your body would burn if you lay completely still for 24 hours. It accounts for roughly 60-70% of total daily calorie burn for most people.
The most accurate formula for calculating BMR is the Mifflin-St Jeor equation, developed in 1990 and validated across multiple large population studies. Once you have your BMR, it's multiplied by an activity multiplier to account for the calories burned through movement and exercise.
| Activity Level | Multiplier | Description |
|---|---|---|
| Sedentary | - 1.2 | Desk job, little or no exercise |
| Lightly Active | - 1.375 | Light exercise 1-3 days per week |
| Moderately Active | - 1.55 | Moderate exercise 3-5 days per week |
| Very Active | - 1.725 | Hard training 6-7 days per week |
| Athlete | - 1.9 | Two-a-day training or physical job |
How To Use Your TDEE
Once you know your TDEE, applying it is straightforward. For fat loss, subtract 300-500 calories from your TDEE to create a daily deficit. This produces roughly 0.3-0.5kg of fat loss per week, a sustainable rate that preserves muscle tissue. Going more than 500 kcal below your TDEE risks muscle loss and metabolic adaptation.
For muscle gain, add 200-350 calories above your TDEE. This modest surplus gives your body the extra energy needed to synthesise new muscle tissue without excessive fat accumulation. For maintenance, simply eat at your TDEE, your weight will stay stable over time.
The most common mistake is choosing the wrong activity multiplier. People consistently overestimate how active they are. If your weight isn't changing as expected after 2-3 weeks, try dropping down one activity category and recalculate.
How Accurate Is TDEE?
The Mifflin-St Jeor equation is accurate to within -10% for most people. Individual metabolism varies, genetics, muscle mass, hormonal factors and gut microbiome all affect actual calorie burn. Treat your calculated TDEE as a starting point, track your weight for 2-3 weeks, and adjust by 100-150 kcal if needed.
Women typically have a slightly lower TDEE than men at the same weight due to lower average muscle mass and different hormonal profiles. The Mifflin-St Jeor formula accounts for this with separate constants for each sex.
