Total daily energy expenditure is every calorie you burn in a day — resting metabolism, movement, training, digestion, fidgeting. It’s the number a calorie target is built from, and getting it roughly right is the difference between a plan that works and one that stalls.
Daily Calorie Needs
Total daily energy expenditure, then what to eat to hold, lose or gain.
Method: Mifflin–St Jeor BMR × an activity multiplier (1.2 to 1.9). Deficits are capped so the suggested intake never drops below 1,500 kcal for men or 1,200 kcal for women — below that it is very hard to hit basic nutrient needs without supervision.
Estimates only — general education, not medical advice. Talk with your doctor before changing how you eat or train. More tools at whatshouldiweigh.com.
The two pieces
Resting metabolism (BMR) is what your body spends staying alive: heart, brain, kidneys, liver, lungs, temperature regulation. For most people it’s 60–70% of the daily total, which surprises people who assume exercise dominates. It doesn’t.
Everything else is movement — deliberate training plus all the incidental activity of a day. This calculator estimates it by multiplying your BMR by an activity factor.
The calculator uses the Mifflin-St Jeor equation for the resting portion, which the Academy of Nutrition and Dietetics recommends as the default for healthy adults:
- Men: (10 × weight in kg) + (6.25 × height in cm) − (5 × age) + 5
- Women: (10 × weight in kg) + (6.25 × height in cm) − (5 × age) − 161
It predicts measured resting metabolism within 10% for most people. Not all. Individual metabolisms vary by roughly that much in either direction for reasons no formula captures.
The activity multiplier is where people go wrong
The multiplier is the least precise part of the calculation and the part with the largest effect. Choosing 1.725 instead of 1.55 adds several hundred calories a day to your target.
| Multiplier | Label | What it honestly means |
|---|---|---|
| 1.2 | Sedentary | Desk job, no structured exercise, low daily step count |
| 1.375 | Light | 1–3 sessions a week, or a job on your feet |
| 1.55 | Moderate | 3–5 real sessions a week |
| 1.725 | Hard | 6–7 sessions a week, or hard training plus an active job |
| 1.9 | Athlete | Physical labour, or two training sessions most days |
Almost everyone picks one tier too high. Three gym sessions a week alongside a desk job and 4,000 daily steps is “light to moderate,” not “hard” — the training is a few hundred calories, and the other 23 hours are sedentary.
If you’re unsure, choose the lower option. It’s easier to add calories when the scale drops faster than you wanted than to work out why a deficit isn’t producing one.
Turning TDEE into a target
Once you have maintenance, goals are adjustments from it:
- Fat loss: roughly 15–25% below maintenance. A 500 kcal daily deficit maps to about a pound a week.
- Maintenance: eat at the number.
- Muscle gain: roughly 10–20% above, paired with resistance training. Larger surpluses add fat faster than muscle.
The calculator won’t suggest an intake below 1,500 kcal for men or 1,200 for women. Below those levels it becomes genuinely hard to hit protein and micronutrient needs without supervision, and the trade-offs stop being worth it.
Calibrate it — the estimate is a starting point
This is the step most people skip, and it’s the one that makes the number yours.
Week 1–2. Eat at your calculated maintenance. Weigh yourself each morning under the same conditions and take a weekly average. Daily readings swing two to four pounds on hydration, sodium and gut contents alone — the average is the signal.
End of week 2. Compare weekly averages. Stable means your maintenance estimate was close. Drifting up or down means adjust by 100–200 kcal in the opposite direction.
From there. You now have a number derived from your actual body rather than a population regression. It’s worth more than any calculator output.
Why the number falls as you lose weight
A common and demoralising experience: a deficit works for two months, then stops.
Nothing has gone wrong. Several things happen at once:
You’re smaller. A lighter body costs less to run and less to move. Losing 20 pounds might drop your maintenance by 100–150 kcal a day on its own. The deficit you set at the start isn’t a deficit any more.
You move less without noticing. Non-exercise activity — walking, standing, fidgeting, gesturing — tends to fall during a sustained deficit. It’s not a decision, and it can account for a few hundred calories.
Adaptive thermogenesis. Resting metabolism drops slightly more than the loss of tissue alone predicts. The effect is real but usually modest, and smaller than internet discussion suggests.
The fix is to recalculate every 10–15 pounds rather than running one number indefinitely. Adding activity is generally a better lever than cutting food further, because cutting further compounds all three problems.
The limits of the number
Calorie estimates on both sides of the ledger are noisy. Food labels carry a permitted margin of error. Fitness trackers and cardio machines routinely overestimate burn by 20% or more. Your own logging is imperfect even when you’re being careful.
None of that makes the exercise pointless — it makes consistency more important than precision. Log the same way every day and the errors stay roughly constant, so the trend still tells you the truth even if the absolute numbers are off.
Common questions
How many calories should I eat to lose weight? Roughly 15–25% below your maintenance figure. Use the table in the calculator, and never go below the floors it applies.
Is TDEE the same as BMR? No. BMR is resting burn only. TDEE is BMR plus everything you do. TDEE is always the larger number.
Why is my TDEE lower than my friend’s? Body size is the dominant factor, then age, sex and activity. A larger body costs more to run, which is why maintenance calories fall as people lose weight.
Should I eat back the calories my watch says I burned? Generally not in full. Wearables overestimate, and the activity multiplier in your TDEE already accounts for training. Eating back tracker calories on top double-counts.
How long before I know if the number is right? Two to three weeks of consistent intake and weekly weight averages. Anything shorter is noise.
The calculators on this site are educational estimates, not medical advice. Talk with your doctor or a registered dietitian before making significant changes to how you eat, particularly if you have a medical condition or take medication that affects appetite or metabolism.