Almost every diet argument comes down to one question: how many calories should you eat? Generic answers like “2,000 a day” or “just eat less” ignore the fact that a 60 kg office worker and a 95 kg builder burn completely different amounts of energy. Before any diet can work, you need your own number.
That number is your TDEE — Total Daily Energy Expenditure. It is the total number of calories your body burns in 24 hours, and it is the single figure your entire eating plan should be built around.
What Makes Up Your TDEE?
TDEE has four parts. The biggest is your BMR (Basal Metabolic Rate) — the energy you burn at complete rest just keeping your heart, brain and organs running. It typically makes up 60–70% of your total. On top of that sits everyday movement (walking, standing, fidgeting), formal exercise, and the small amount of energy used to digest food, roughly 10% of what you eat. Most people underestimate how much the everyday movement part matters: two people with identical gym routines can differ by several hundred calories a day because one has an active job and the other sits all day.
How TDEE Is Calculated
First, your BMR is estimated with the Mifflin-St Jeor equation. For men: (10 × weight in kg) + (6.25 × height in cm) − (5 × age) + 5. For women the same formula ends with − 161 instead of + 5. That BMR is then multiplied by an activity factor: 1.2 for sedentary, 1.375 for lightly active, 1.55 for moderately active, 1.725 for very active, and 1.9 for athletes or physical jobs combined with hard training.
Take a 28-year-old woman, 65 kg and 168 cm. Her BMR is 650 + 1,050 − 140 − 161 = 1,399 kcal. Training three to five times a week, her TDEE is 1,399 × 1.55 ≈ 2,168 kcal a day. To lose fat she would eat about 20% less — roughly 1,735 kcal. To gain muscle, about 15% more — roughly 2,494 kcal. Our TDEE Calculator runs exactly this calculation for your own stats in seconds.
One honest warning: every formula is an estimate, typically within about ±10%. Treat your first TDEE as a starting point, eat at it consistently for two weeks, and adjust by 100–200 kcal based on what your weight actually does.
Stop guessing with generic calorie targets. Work out your real number with the TDEE Calculator, set your goal, and you have the foundation every sensible diet is built on. (These are estimates for planning, not medical advice.)