TDEE Calculator
Estimate how many calories your body burns in a day using the Mifflin-St Jeor equation — the most validated formula for resting metabolic rate. Adjust for your activity level and goal.
Your Stats
Activity Level
What is TDEE and why does it matter?
TDEE stands for Total Daily Energy Expenditure — the total number of calories your body burns every 24 hours. It includes your basal metabolic rate (the energy needed just to keep you alive), the thermic effect of food (calories burned digesting meals), and all physical activity from training to walking to fidgeting. If you eat more than your TDEE you gain weight; eat less and you lose it. Every effective nutrition plan starts with knowing this number.
How does age affect your maintenance calories?
Basal metabolic rate drops roughly 1–2% per decade after your twenties, mostly because of gradual muscle loss. By 40, most people burn 200–300 fewer calories at rest than they did at 25. The good news: resistance training offsets much of this decline. Building or maintaining muscle tissue keeps your metabolic rate elevated. This is why strength training becomes even more important — not less — as you age.
Why static TDEE formulas are just an estimate
The Mifflin-St Jeor equation used in this calculator is the most validated formula for estimating resting metabolic rate, but it still relies on population averages. It cannot account for your individual levels of NEAT (non-exercise activity thermogenesis), metabolic adaptation during a calorie deficit, hormonal fluctuations, sleep quality, or chronic stress — all of which can shift your actual energy expenditure by 200–400 calories per day. A static calculator gives you a starting point. Tracking your real intake and weight trends over time gives you the truth.
How to use your TDEE estimate
For fat loss, subtract 400–500 calories from your TDEE. For a lean bulk, add 200–300 calories. For maintenance, eat at your estimated TDEE and monitor your weight over two weeks — if it stays flat, you've found your baseline. Adjust in increments of 100–200 calories based on weekly weigh-in trends, not daily fluctuations. Consistency and patience matter more than precision on day one.