How calories are calculated
First, the basal metabolic rate is calculated — how much energy your body uses at rest. The calculator uses the Mifflin–St Jeor equation, considered the most accurate for adults:
The basal rate is then multiplied by an activity factor — from 1.2 for desk work to 1.9 for daily training. This gives the intake needed to maintain your weight. To lose weight you need a deficit: roughly 7,700 kcal per kilogram of fat. A pace of 0.5 kg a week means a deficit of about 550 kcal a day.
A safe pace
Doctors recommend losing no more than 0.5–1 kg a week. With faster weight loss you lose muscle and water, your metabolism slows down, and the weight often comes back. That’s why the calculator doesn’t go below 1,200 kcal for women and 1,500 kcal for men, and won’t make a plan if the target weight is below the healthy range for BMI.
What matters more than calories
- Protein at every meal helps preserve muscle and keeps you full for longer.
- 7–9 hours of sleep: lack of sleep increases appetite.
- Walking 7,000–10,000 steps a day increases energy use without exhausting workouts.
If you have a chronic condition, are pregnant or breastfeeding, discuss weight loss with a doctor. The calculator is not suitable for children and teenagers.