Calorie Calculator

Guide: Calorie Calculator

How the estimate is built

The calculator first estimates your basal metabolic rate (BMR), the calories you burn at rest, then scales it by how active you are to get maintenance calories (TDEE), and finally adjusts for your goal.

The formulas

• BMR (Mifflin-St Jeor): 10 × kg + 6.25 × cm − 5 × age, then +5 for men or −161 for women
• TDEE: BMR × activity factor (1.2 sedentary, 1.375 light, 1.55 moderate, 1.725 very active, 1.9 extra active)
• Goal calories: TDEE + (kg per week × 7,700 ÷ 7)

Example: a 30-year-old man, 80 kg, 180 cm: BMR = 800 + 1,125 − 150 + 5 = 1,780 kcal. At moderate activity (1.55) maintenance is about 2,759 kcal.

Choosing a goal

A loss of 0.5 kg per week means about 550 kcal below maintenance each day; gaining 0.25 kg per week is about 275 above. Smaller steps are easier to keep. The example macronutrient split (25% protein, 45% carbohydrate, 30% fat) uses 4 kcal per gram of protein and carbohydrate and 9 per gram of fat; it is a starting point, not a prescription.

Health disclaimer

This tool gives an estimate for healthy adults only. Individual needs vary with body composition, medication and health conditions. It is not medical advice. Consult a qualified professional before changing your diet, and do not use it for children, pregnancy or eating disorders.

FAQ

What is the Mifflin-St Jeor equation?

BMR = 10 × weight(kg) + 6.25 × height(cm) − 5 × age + 5 for men or − 161 for women. It is widely considered one of the more accurate formulas for estimating resting energy use.

What is the difference between BMR and TDEE?

BMR is the energy your body burns at rest. TDEE (total daily energy expenditure) is BMR multiplied by an activity factor from 1.2 to 1.9 and equals your maintenance calories.

How many calories make a kilogram of weight?

About 7,700 kcal per kg (3,500 kcal per pound) of body weight. Real results vary because metabolism adapts.

How fast is it safe to lose weight?

Many guidelines suggest around 0.25–1 kg (0.5–2 lb) per week at most. The calculator warns when the target goes below 1,200 kcal (women) or 1,500 kcal (men).

Is this medical advice?

No. It is an estimate for healthy adults. See a doctor or registered dietitian for personal guidance, especially if you are pregnant, under 18 or have a medical condition.