Free calculator
Calorie calculator: how many calories should I eat a day?
How the calculator works
It follows four steps, exactly as Doydum builds your plan:
- Resting energy (BMR) with the Mifflin–St Jeor formula: 10 × weight in kg + 6.25 × height in cm − 5 × age, then +5 for men or −161 for women.
- Daily energy (TDEE): resting energy × an activity multiplier (1.2 sitting most of the day, 1.375 lightly active, 1.55 moderately active, 1.725 very active, 1.9 extra active).
- Your pace: to lose or gain, the day changes by pace × 7,700 kcal ÷ 7. That is 275, 550 or 825 kcal a day for 0.25, 0.5 or 0.75 kg a week.
- A floor: the estimate never goes under 1,200 kcal (female formula) or 1,500 kcal (male formula).
A worked example
| Step | Value |
|---|---|
| Resting energy | 1,855 kcal |
| × 1.375 (lightly active) | 2,551 kcal |
| − 0.5 kg a week | −550 kcal |
| Daily calories | 2,001 kcal |
| Protein · carbs · fat | 150 · 200 · 67 g |
| Water | 2.95 L |
Why it is an estimate
Formulas predict the average person of your size and age; you are not an average. Treat the number as a starting point: log honestly for two or three weeks, watch the trend of your weight and adjust by 100 to 200 kcal if it moves faster or slower than you planned. The "7,700 kcal per kg" rule is a simplification too, and change usually slows as you go.
If you are pregnant, breastfeeding, under 18, living with a medical condition or an eating disorder, ask a doctor or registered dietitian before following any calorie number.
Frequently asked questions
How many calories should I eat to lose weight?
Start from your daily energy (TDEE) and take away a gentle amount: 275 to 550 kcal a day corresponds to about 0.25 to 0.5 kg a week. Doydum never goes under 1,200 kcal (female formula) or 1,500 kcal (male formula).
Is this the same number the Doydum app gives me?
Yes. The calculator runs the app’s own plan code: same formula, same activity multipliers, same pace adjustment and the same minimums. In the app you can change your targets at any time.
What is the Mifflin–St Jeor formula?
A 1990 equation for resting energy that is widely used because it predicts better than older formulas for most adults: 10 × kg + 6.25 × cm − 5 × age, +5 for men or −161 for women.