How it works
First the calculator estimates your basal metabolic rate (the energy your body uses at complete rest) with the Mifflin-St Jeor equation, one of the most widely used and validated formulas. It then multiplies it by your activity level to estimate your maintenance calories, the amount that keeps your weight stable.
Activity factors
| Activity level | Factor |
|---|---|
| Sedentary | 1.2 |
| Lightly active | 1.375 |
| Moderately active | 1.55 |
| Very active | 1.725 |
| Extremely active | 1.9 |
Most people overestimate how active they are, so if you are torn between two levels, choose the lower one.
Safe limits
Weight-loss targets are capped at a moderate deficit, and the calculator never suggests going below 1,500 kcal a day for men or 1,200 for women without medical supervision. If your BMI is in the underweight range, it shows no weight-loss targets at all.
Frequently Asked Questions
What is the difference between BMR and maintenance calories?
BMR is what your body burns at complete rest. Maintenance calories add the energy you use in daily activity and exercise, which is why they are always higher.
Why don’t I see weight-loss options?
If your BMI is in the underweight range, or your needs are close to the minimum safe intake, the calculator does not suggest a deficit. A doctor or dietitian can advise you directly.
Is it suitable for under-18s?
No. Teenagers are still growing and have different needs, so the calculator is limited to adults 18 and over.
Is the number exact?
No formula is exact for every person. Treat the result as a starting point, then adjust based on how your weight changes over a few weeks.
Does this include my workouts?
Your activity level already covers your usual exercise roughly. To see what a specific workout burned, use our calories burned calculator.