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What you burn in a day.
TDEE is total daily energy expenditure: everything your body spends in 24 hours, resting and moving. This uses the Mifflin-St Jeor equation and an activity factor, which is the same arithmetic the CalorieCounter app runs when it sets a target.
Everything here runs in your browser. Nothing you enter is uploaded, nothing is stored, and there is no sign-up. These are estimates from published equations, not medical advice.
What is TDEE, in plain terms?
TDEE stands for total daily energy expenditure: every calorie your body spends in 24 hours. It is your resting energy, which is roughly 60 to 70 percent of the total for most people, multiplied by a factor for everything you do on top of lying still. Eat that much and your weight holds steady.
The number above is an estimate built from 5 inputs. It cannot see your muscle mass, your thyroid, how well you slept, or how much you fidget, all of which move real energy expenditure around. Treat it as a starting hypothesis and let 2 or 3 weeks of logged data correct it.
How is TDEE calculated?
In two steps. First the Mifflin-St Jeor equation estimates resting energy from weight, height, age and sex. Then that figure is multiplied by an activity factor between 1.2 for a desk-bound week and 1.9 for a physical job or two training sessions a day. The product is your TDEE.
| Activity factor | A week that looks like |
|---|---|
| 1.2 | Desk work, little or no exercise |
| 1.375 | Exercise 1 to 3 days a week |
| 1.55 | Exercise 3 to 5 days a week |
| 1.725 | Hard exercise 6 or 7 days a week |
| 1.9 | Physical job, or two sessions a day |
If you are between two buckets, pick the lower one. Overestimating activity is the single most common reason a calorie target quietly stops working.
How accurate is a TDEE calculator?
Close enough to start with, and wrong enough that you should check it. Prediction equations typically land within about 10 percent of measured resting energy for most people, which on a 2,000 calorie day is a swing of roughly 200 calories. Individual error can be larger, particularly at very high or very low body weights.
The fix is not a better formula. It is 2 to 3 weeks of consistent logging alongside a weight trend. If the trend does not move while you eat at your predicted TDEE, your real TDEE is lower than the estimate, and you adjust by 100 to 200 calories rather than starting again.
What do you do with the number once you have it?
Subtract to lose, add to gain, leave it alone to maintain. A kilo of body fat holds roughly 7,700 calories, so half a kilo a week works out at about 550 calories a day either side of your TDEE. Gaining only adds much muscle if training and protein are there too.
The full calorie calculator does that arithmetic for you and applies a floor, refusing to return a target under 1,200 calories for women or 1,500 for men. Once you have a target, the macro calculator turns it into grams.
Why does a TDEE that worked stop working?
Because the inputs move. Losing 10 kilograms lowers resting energy by roughly 100 calories a day on its own, and people tend to move less without noticing when they are eating less. The equation cannot see either, so a target set in January quietly becomes a maintenance target by March.
This is why a static number is worse than a logged trend. Recheck the calculation after every 5 kilograms of change, and if the weight trend has been flat for 3 weeks while you are hitting your target, cut 100 to 200 calories rather than assuming the logging is wrong.
FAQ
Is TDEE the same as maintenance calories?
Yes. They are two names for the same figure: the calories that hold your weight steady over time. TDEE is the physiological term, maintenance is what most apps and coaches call it.
Should I eat back the calories I burn exercising?
Not if your activity factor already accounts for that exercise, which it does here. Adding tracked workout calories on top of a factor that already includes them counts the same training twice, and watch-estimated burn is often generous.
Why is my TDEE different on another site?
Most differences come from the equation. Harris-Benedict, Katch-McArdle and Mifflin-St Jeor all return slightly different resting numbers, and Katch-McArdle needs a body fat percentage. This page uses Mifflin-St Jeor, published in 1990.
Sources
- Mifflin MD et al., A new predictive equation for resting energy expenditure in healthy individuals, American Journal of Clinical Nutrition, 1990
- Dietary Reference Intakes for Energy, Carbohydrate, Fiber, Fat, Protein and Amino Acids, National Academies
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