TDEE stands for total daily energy expenditure: the total number of calories your body burns in a day. It includes everything — keeping your organs running, walking to the kettle, your workout, even digesting your food. Eat below your TDEE and you lose weight; eat above it and you gain. Every diet that has ever worked, worked because of this number.
Most people start a diet by choosing what to cut — carbs, sugar, entire food groups. That's backwards. Start by learning what you burn, and suddenly every eating decision has a reference point. That's what TDEE gives you.
Want yours right now? The TDEE calculator takes about a minute. Then come back — this page explains what the number actually means.
The four things your body spends calories on
Your TDEE isn't one process. It's four, and knowing the split explains a lot about why weight loss works the way it does.
| Component | Share of TDEE | What it is |
|---|---|---|
| BMR — basal metabolic rate | ~60–70% | The cost of being alive: heart, brain, breathing, cell repair — what you'd burn in bed all day |
| NEAT — non-exercise activity | ~15–30% | All movement that isn't exercise: walking, cleaning, fidgeting, standing |
| TEF — thermic effect of food | ~10% | The energy cost of digesting what you eat |
| Exercise | ~5–10% for most people | Deliberate workouts |
Two things in that table surprise almost everyone.
First: exercise is the smallest slice. A hard 45-minute session might burn 300–400 kcal — real, but small next to the 1,500+ your BMR quietly burns regardless. This is why "I'll out-train a bad diet" fails so reliably, and why the eating side of weight loss matters more than the gym side. (Training still matters enormously — just for muscle, health and keeping weight off, not as a calorie eraser.)
Second: NEAT is bigger than exercise — and it's sneaky. The difference between an active job and a desk job can be several hundred calories a day. NEAT also quietly drops when you diet hard: your body nudges you to fidget less and sit more. You don't notice it happening, but your TDEE does.
How TDEE is estimated
You can't measure your true TDEE without a metabolic lab, but you can estimate it well. The standard approach — the one our calculator uses — is the Mifflin-St Jeor equation, which research from the Academy of Nutrition and Dietetics rates as the most reliable everyday formula. It estimates your BMR from your age, sex, height and weight, then multiplies by an activity factor between 1.2 (sedentary) and 1.9 (extremely active).
The result is typically within about 10% of reality. Treat it as a strong starting point: follow it for two or three weeks, watch the trend on the scale, and adjust by 100–200 kcal if needed. Your real-world results are the final calibration no formula can match.
Using your TDEE to lose weight
Here's the entire strategy in three lines:
- Find your TDEE — say it's 2,300 kcal.
- Eat 300–500 below it — so 1,800–2,000 kcal a day.
- Expect around 0.25–0.5 kg (0.5–1 lb) per week, the pace the NHS and CDC both recommend as sustainable.
That's a "moderate deficit", and it beats aggressive cutting for one simple reason: you can actually keep doing it. A 1,200-kcal crash diet works right up until the evening it doesn't — then the rebound eats the progress. A moderate deficit leaves you room for protein, for training, and for a life.
Example in all three unit systems: a woman of 38, 76 kg (168 lb / 12 st), 165 cm, lightly active, has a TDEE around 2,000 kcal. At 1,600 kcal a day she loses roughly 0.4 kg (just under a pound) a week — about 5 kg in three months, eating four meals a day, no food banned.
What should those calories be made of? That's the next lesson: what are macros?
The catch: TDEE is a moving target
This is the part most sites skip, and it's the reason most "plateaus" happen.
As you lose weight, your TDEE falls. A 90 kg body burns more than an 80 kg body — there's simply less of you to run. Lose 5–10 kg and your TDEE can drop by a couple of hundred calories. The deficit you set in January quietly shrinks by spring, weight loss slows, and it feels like your body is broken. It isn't. Your numbers are just out of date.
The fix is boring and effective: recalculate every 4–6 weeks, or after every ~5 kg / 11 lb / most-of-a-stone lost, and reset your intake to match. If you've stalled for three weeks or more and your tracking is honest, stale numbers are the first suspect to rule out.
FAQ
Is TDEE the same as metabolism?
Close enough for everyday use. "Metabolism" technically means all the chemical processes in your body; TDEE is the calorie cost of them, per day. When people say "fast metabolism", they mean a high TDEE.
Is 2,000 calories a normal TDEE?
It's the population-average label used on food packaging, but individual TDEEs range from about 1,400 to well over 3,000 depending on size, muscle, age, sex and activity. That's exactly why calculating your own beats following the label.
Does muscle really increase TDEE?
Yes — muscle tissue costs more energy to maintain than fat, at rest and especially in use. It's one of the strongest arguments for strength training while losing weight: it protects the engine that burns the fuel.
Can my TDEE be damaged by past dieting?
"Metabolic damage" is largely a myth, but adaptation is real: hard dieting temporarily lowers NEAT and slightly lowers BMR. The effect mostly reverses with time at maintenance. If you've crash-dieted for years, expect your true TDEE to sit a little under formula estimates at first — and be patient with it.
Written by Ricky Valentine · Reviewed against sources below · Last updated 31 August 2026
Citations to verify in edit pass: Mifflin-St Jeor (1990, Am J Clin Nutr); Academy of Nutrition and Dietetics formula comparison; NHS weight-loss pace guidance; CDC healthy-weight guidance; a NEAT reference (Levine's research is standard).