What your daily burn is made of
Total daily energy expenditure, TDEE, is every calorie your body spends in twenty-four hours. It has four ingredients, and the proportions surprise most people.
- Resting metabolism (BMR), roughly 60 to 70 percent. The cost of being alive: heartbeat, breathing, brain, body temperature. It runs whether you move or not.
- Everyday movement (NEAT), roughly 10 to 20 percent. Walking to the shop, fidgeting, cooking, standing. This varies wildly between people and explains most "fast metabolism" stories.
- Digesting food, roughly 10 percent. Processing what you eat costs energy, and protein costs the most to process.
- Actual exercise, often just 5 to 10 percent. The gym matters, but less than the other three combined, which is why "I trained today" rarely licenses a large dessert.
How the number is worked out
The calculator first estimates your resting burn with the Mifflin-St Jeor equation, the one with the best accuracy record in validation studies:
Then it multiplies by your activity factor, from 1.2 for sedentary through to 1.9 for extremely active, to cover everything you do beyond lying still. The revised Harris-Benedict equation and the lean-mass-based Katch-McArdle formula sit under "Fine-tune the formula", and the comparison table in the results shows all three, because seeing the spread is the fastest cure for treating any one of them as gospel.
Choose your activity level honestly
The multiplier is where daily-calorie calculators go wrong, and it is nearly always chosen too high. A desk job plus three gym sessions a week feels active, but it averages out to lightly-to-moderately active at best. The training hours are outnumbered by the sitting hours a hundred to five.
Two honest rules of thumb. If you are unsure between two levels, pick the lower one. And if you have a step counter, let it vote: under 5,000 steps most days is sedentary, around 7,500 is light, past 10,000 with regular training is moderate or better.
Then run the two-week audit. Eat your calculated TDEE, weigh in daily, and average each week. Weight steady means the number is right. Weight drifting up by a quarter kilo a week means you are eating roughly 275 kcal over true maintenance; adjust the number, not your conscience.
What to do with your number
Holding steady: eat your TDEE and lean on protein and fibre so the calories keep you full. Losing: the ready-made targets in the results use safe default deficits, and the Calorie Deficit Calculator turns them into a dated, charted plan. Gaining: add 250 to 500 kcal over TDEE, keep protein at 1.6 to 2.2 g per kilogram, and expect roughly a quarter to half a kilo a week; faster gain is mostly fat.
Why your watch disagrees
Wrist trackers routinely read exercise burn 20 to 40 percent high, then add it to an estimate of your resting burn that already included some movement. Double counting plus optimism is how a watch hands you a 3,200 kcal day for a desk job and a 5k run. Trust the equation first, then let three weeks of scale data overrule everyone, the watch and this page included.
Questions people ask
Should I eat the same amount every day?
TDEE is an average, so your intake only has to average out. Eating 200 over on Saturday and 200 under on Monday lands in the same place. Many people run slightly lower on rest days and higher on training days purely for appetite comfort; the week decides, not the day.
What is the difference between BMR and TDEE?
BMR is the energy cost of existing: what you would burn in bed all day. TDEE is BMR plus all movement and digestion. You eat at TDEE to maintain weight, never at BMR, which would be a severe deficit for almost everyone.
How accurate is this really?
Mifflin-St Jeor lands within about 10 percent of measured values for most adults, and the activity multiplier adds the bigger error bar. Treat the result as a well-informed starting point with roughly a ±200 kcal margin, then calibrate against two to three weeks of morning weigh-ins.
How often should I recalculate?
After every 4 to 5 kg of weight change, and after any real change in routine: a new job on your feet, an injury, a marathon block. Ten seconds with your new numbers keeps the estimate honest.
Does muscle really burn many extra calories?
Modestly. A kilogram of muscle adds roughly 13 kcal a day at rest, so five hard-earned kilos add about 65 kcal, a small apple. The bigger metabolic wins from training are the session burn itself and the extra everyday movement of being a stronger person.
This tool estimates energy needs for healthy adults. Pregnancy, breastfeeding, thyroid conditions and some medications change the arithmetic; get individual advice for those.