If you've ever wondered how many calories you should eat, the honest answer starts with one number: your Total Daily Energy Expenditure, or TDEE. It's the total amount of energy your body burns in a day, and it's the anchor for every goal — losing fat, gaining muscle, or holding steady.
The good news is that estimating it takes about thirty seconds. The important news is that the estimate is only a starting point. This guide covers both: how the number is calculated, and — more importantly — how to make it actually work for you.
What TDEE is made of
Your daily burn isn't a single process. It's the sum of four components, and understanding them explains why two people of the same weight can need very different amounts of food.
- Basal Metabolic Rate (BMR) — the energy to keep you alive at rest. This is the biggest slice, around 60–70% of TDEE.
- Thermic Effect of Food (TEF) — the energy spent digesting and absorbing what you eat, roughly 10%. Protein has the highest TEF.
- Exercise Activity (EAT) — deliberate training: lifting, running, cycling.
- Non-Exercise Activity Thermogenesis (NEAT) — everything else you move: walking, fidgeting, standing, chores. NEAT varies enormously between people.
Why NEAT matters more than you think
NEAT can differ by up to 2,000 calories a day between two similar people. It's also the component that quietly drops when you diet — you move less without noticing — which is a major reason fat loss stalls.
The formula
We estimate BMR with the Mifflin–St Jeor equation, the best-validated predictive formula for the general population, then multiply by an activity factor.
- BMR (men) = 10 × weight(kg) + 6.25 × height(cm) − 5 × age + 5
- BMR (women) = 10 × weight(kg) + 6.25 × height(cm) − 5 × age − 161
- TDEE = BMR × activity factor (1.2 sedentary → 1.9 athlete)
TDEE Calculator
Skip the arithmetic — plug your details in and get your maintenance and goal calories instantly.
The mistake almost everyone makes
The activity multiplier is where estimates go wrong. Most people dramatically overrate their activity level. Training hard four times a week feels active, but across a full 24-hour day — most of which you spend sitting — you may still land closer to 'lightly active' than 'very active'.
When in doubt, round down
Pick the lower activity multiplier. It's far easier to add calories when the scale isn't moving than to figure out why an aggressive estimate isn't producing results.
How to turn the estimate into your real number
No equation knows your exact metabolism. Treat the calculated TDEE as a hypothesis and test it against reality over two to three weeks.
- Eat at your estimated maintenance for 14–21 days, tracking intake as accurately as you reasonably can.
- Weigh yourself daily, first thing in the morning, and take a 7-day average to cut through water fluctuations.
- If the weekly average is stable, your estimate was good. If it's rising, your true TDEE is lower — subtract ~150–200 calories. If it's falling, add them.
- Once maintenance is dialled in, apply your goal: a 10–20% deficit for fat loss, or a 5–15% surplus for lean gains.
“The scale is the feedback loop. The formula gets you in the right neighbourhood; your own trend line finds the exact address.”
Recalculate as you change
TDEE isn't fixed. As you lose weight, there's less of you to fuel, so your maintenance drops. Recalculate every 3–4 kg of change, or every 4–6 weeks, and re-test. This is why a deficit that worked in week one can stop working by week eight — the target moved.
Get comfortable with this cycle — estimate, test, adjust, repeat — and you'll never be at the mercy of a calculator or a fad diet again. You'll have a system.