What makes up your daily burn
TDEE is the sum of four things:
- Basal metabolic rate (BMR): the energy your body uses at rest, usually the largest share. See the BMR calculator.
- Thermic effect of food: the energy spent digesting and absorbing what you eat, commonly about a tenth of your intake.
- Exercise: planned workouts. For most people this is a smaller share than they expect.
- Everyday movement: walking, standing, chores, fidgeting. It is the most variable part, and two people of the same size can differ by several hundred calories a day here.
This calculator does not measure each part. It estimates BMR and multiplies it by an activity factor that stands in for the other three.
Choosing your activity level
Pick the level that matches your whole week, not your best week. The step counts are a rough guide only.
| Level | Factor | What it looks like | Typical daily steps |
|---|---|---|---|
| Sedentary | × 1.2 | Desk job, little exercise, you mostly sit | under 5,000 |
| Lightly active | × 1.375 | Light exercise 1 to 3 days a week, or a job with some walking | 5,000 to 7,500 |
| Moderately active | × 1.55 | Exercise 3 to 5 days a week, or a job on your feet most of the day | 7,500 to 10,000 |
| Very active | × 1.725 | Hard training 6 to 7 days a week, or a physically active job | 10,000 to 12,500 |
| Extra active | × 1.9 | Physical job plus daily training, or two sessions a day | over 12,500 |
The factors are conventions that have been used since the Harris–Benedict era, not precise measurements. If you are between two levels, take the lower one. Overestimating activity is the most common reason a “maintenance” number turns out to be too high.
The formula
TDEE = BMR × activity factorBMR uses the Mifflin–St Jeor equation: 10 × weight (kg) + 6.25 × height (cm) − 5 × age, then + 5 for men or − 161 for women.
Worked example: why the activity level matters most
A 27-year-old man, 183 cm tall, weighing 76 kg, who trains six days a week.
- BMR = 10 × 76 + 6.25 × 183 − 5 × 27 + 5 = 1,774 kcal
- Very active (× 1.725): 1,774 × 1.725 = 3,060 kcal a day
If he had chosen “sedentary” (× 1.2) the answer would have been 2,129 calories, which is 931 calories lower. Choosing between activity levels moves the result far more than any detail of the equation, which is why your result shows every level side by side.
Check it against your own body in three weeks
An estimate is a starting point. You can turn it into a measured number:
- Weigh yourself every morning for three weeks, after using the toilet and before eating.
- Weigh and log everything you eat, and keep your training and routine normal.
- Compare the average weight of the first week with the average of the third week.
- Convert the change into daily calories: change in kg × 7,700 ÷ 21 days.
For example, if you averaged 2,600 calories a day and your weight rose 0.3 kg over three weeks, that is about 110 extra calories a day, so your maintenance is close to 2,490. Be aware that most people under-record what they eat, so if the figure looks low, trust the scale before the diary.
Why your TDEE changes
- Weight. A lighter body burns less, so recalculate after every 5 kg or so.
- Muscle. Gaining or losing muscle shifts BMR and the cost of moving.
- Everyday movement. It tends to fall when you diet and rise when you eat more, which narrows the gap you were aiming for.
- Life. A new job, a holiday, an injury, a stretch of illness and ageing all move the number.
These results are general estimates for healthy adults, not medical advice. See the disclaimer for who should check with a professional first.