How the calorie calculator works
The tool uses the Mifflin-St Jeor equation to estimate your basal metabolic rate (BMR): 10 × kg + 6.25 × cm − 5 × age + 5 for men, and … − 161 for women. BMR is then multiplied by an activity factor (1.2 for sedentary up to 1.9 for extra active) to get your TDEE, the calories you burn in a typical day. Eating around your TDEE keeps your weight steady.
Losing or gaining weight
One kilogram of body fat is about 7,700 kcal, so changing your intake by 550 kcal a day moves your weight by about 0.5 kg a week. Most dietitians suggest 0.25 to 0.5 kg per week. Faster than that usually costs muscle and energy. If the target falls below 1,200 kcal (women) or 1,500 kcal (men), the tool uses that minimum instead and shows a warning.
Tips
- Choose your activity level honestly. Most students and office workers are "sedentary" or "lightly active".
- Weigh yourself at the same time each morning and look at the weekly trend, not daily jumps.
- Roti, rice, oil and sweet drinks add up fast. Tracking for a few days shows where the extra calories come from.
- The macro split shown (25 percent protein, 45 percent carbs, 30 percent fat) is only a starting point.
This is an estimate for healthy adults and not medical advice.
Frequently asked questions
What is the Mifflin-St Jeor equation?
It estimates your basal metabolic rate (BMR), the calories you burn at complete rest: 10 × weight (kg) + 6.25 × height (cm) − 5 × age + 5 for men or − 161 for women. It is considered one of the most reliable simple formulas for healthy adults.
What is the difference between BMR and TDEE?
BMR is what your body burns just to stay alive. TDEE (total daily energy expenditure) is BMR multiplied by an activity factor from 1.2 (desk life) to 1.9 (very hard training). TDEE is roughly the calories you need to keep your weight the same.
How many calories make a kilogram of fat?
About 7,700 kcal. So a daily deficit of 500 kcal leads to roughly 0.5 kg lost per week. Real results vary because your body adapts.
Why does the tool stop me going below 1,200 or 1,500 calories?
Eating much less than that without medical supervision can cause tiredness, muscle loss and nutrient gaps. The tool shows a warning and uses the minimum as a floor for the target.
Does this work for children or teenagers?
No. It is designed for healthy adults aged 18 and over. Growing teenagers need a doctor or dietitian's advice.