Almost every calorie target starts with the same two steps: estimate what your body uses at rest, then multiply that by how much you move. The result is called total daily energy expenditure, or TDEE.
It is worth understanding the calculation rather than just reading a number, because the number is an average for people who look like you on paper — not a measurement of you.
Step 1: estimate your basal metabolic rate
Basal metabolic rate (BMR) is the energy your body uses to keep you alive at complete rest. The most widely used estimate is the Mifflin-St Jeor equation, which takes weight, height, age and sex.
For men: 10 × weight in kg + 6.25 × height in cm − 5 × age + 5. For women, the same equation ends in −161 instead of +5.
Step 2: multiply by your activity level
BMR only covers rest. To estimate a whole day you multiply it by an activity factor that includes both training and everything else you do — walking, standing, housework, your job.
- Mostly sitting, little exercise: about 1.2
- Light activity or training 1–3 days a week: about 1.375
- Moderate activity or training 3–5 days a week: about 1.55
- Hard training 6–7 days a week: about 1.725
- Physical job plus daily training: about 1.9
Step 3: adjust for your goal
Eating roughly your TDEE should keep your weight fairly stable. A moderate deficit of 10–20% below it is a common starting point when the goal is to lose weight, and a small surplus is used when the goal is to gain.
Very large deficits are not automatically better. They are harder to keep up, harder to combine with training, and they usually cost you more of the food variety that makes the plan livable.
Step 4: replace the estimate with your own data
This is the step most people skip. Track what you actually eat and weigh yourself under the same conditions a few times a week for two to four weeks, then compare weekly averages rather than individual days.
If your weekly average has not moved the way you expected, adjust intake by roughly 100–200 kcal and give it another two weeks. That correction is worth more than any equation, because it is measured on you.