📖 How TDEE Calculator Works
Total Daily Energy Expenditure (TDEE) represents the total number of calories your body burns in a 24-hour period, including your basal metabolic rate (BMR) plus all physical activity. Knowing your TDEE is the single most important number for any diet or fitness goal.
The Mifflin-St Jeor Formula (Most Accurate)
The Mifflin-St Jeor equation (1990) is considered the most accurate for the general population, outperforming the older Harris-Benedict equation in clinical studies.
Activity Multipliers Explained
Sedentary (1.2): Office job, minimal movement. Lightly active (1.375): Walking, light gym 1–3 days/week. Moderately active (1.55): Consistent gym 3–5 days/week. Very active (1.725): Daily intense training or physical labor. Extra active (1.9): Athletes training twice daily or extremely demanding physical jobs.
Creating a Calorie Deficit
One pound of fat contains approximately 3,500 calories. A deficit of 500 calories per day creates a 3,500-calorie/week deficit — theoretically resulting in 1 lb of fat loss per week. In practice, metabolic adaptation means the actual result is slightly less, but this remains the gold-standard guideline used by dietitians worldwide.
❓ How accurate is TDEE?
TDEE calculators provide estimates with a margin of error of around 10–15%. Your actual TDEE can vary based on non-exercise activity thermogenesis (NEAT), hormonal status, gut biome, and metabolic adaptation. The best approach is to track calories and weight for 2–4 weeks and adjust accordingly.
❓ Should I eat back exercise calories?
If you've used an accurate activity multiplier (e.g., "Very Active"), your workout calories are already built into your TDEE. Only add extra calories back if you significantly underestimated your activity level.