How to Calculate Your Daily Calorie Needs
Your daily calorie needs represent the total number of calories your body requires each day to function and maintain your current weight. Knowing this value is essential for any goal: losing weight, maintaining weight, or building muscle.
The Mifflin-St Jeor Formula
This calculator uses the Mifflin-St Jeor equation (1990), recommended as the most accurate formula for adults:
- Men: BMR = 10 x weight(kg) + 6.25 x height(cm) - 5 x age + 5
- Women: BMR = 10 x weight(kg) + 6.25 x height(cm) - 5 x age - 161
The result (BMR) is then multiplied by the activity factor to obtain the TDEE (Total Daily Energy Expenditure):
- Sedentary: x 1.2
- Lightly active: x 1.375
- Moderately active: x 1.55
- Very active: x 1.725
- Extremely active: x 1.9
How This Calculator Works
Enter your sex, age, weight, height, and physical activity level. The calculator determines your basal metabolic rate using the Mifflin-St Jeor formula and multiplies it by the selected activity factor. You will receive:
- Your basal metabolic rate (calories burned at rest)
- Your total daily energy expenditure (TDEE)
- Calories needed to lose weight (500 kcal deficit)
- Calories needed to gain weight (500 kcal surplus)
How to Use This Information
Your TDEE is the starting point for any meal plan. Eating at your TDEE keeps your weight stable. Eating less (caloric deficit) leads to weight loss; eating more (caloric surplus) leads to weight gain. A deficit or surplus of 500 kcal per day produces approximately 0.5 kg (about 1 lb) of weight change per week.
Safety Guidelines
Never go below 1,200 kcal/day for women or 1,500 kcal/day for men without medical supervision. Extreme calorie restriction can slow your metabolism, cause muscle loss, and lead to nutritional deficiencies. Always consult a healthcare professional before starting a significant dietary change.