How Many Calories Do You Need Per Day?
The number of calories you need depends on your age, gender, height, weight, and activity level. Our calculator uses the Mifflin-St Jeor equation, which is considered the most accurate formula for estimating Basal Metabolic Rate (BMR) and daily calorie needs.
The Mifflin-St Jeor Equation
Men: BMR = (10 × weight in kg) + (6.25 × height in cm) - (5 × age) + 5
Women: BMR = (10 × weight in kg) + (6.25 × height in cm) - (5 × age) - 161
Your BMR is then multiplied by an activity factor to get your Total Daily Energy Expenditure (TDEE) — the total calories you burn per day.
Activity Level Multipliers
- Sedentary (x1.2): Desk job, little exercise
- Lightly active (x1.375): Light exercise 1-3 days/week
- Moderately active (x1.55): Moderate exercise 3-5 days/week
- Very active (x1.725): Hard exercise 6-7 days/week
- Extra active (x1.9): Very intense exercise, physical job
Calorie Deficit for Weight Loss
To lose weight, you need to eat fewer calories than you burn. A deficit of 500 calories/day leads to approximately 0.5 kg (1 lb) of weight loss per week. This is generally considered a safe and sustainable rate of loss.
Important: Never go below 1,200 calories/day for women or 1,500 calories/day for men without medical supervision.
Frequently Asked Questions
How accurate is this calorie calculator?
The Mifflin-St Jeor equation is accurate to within about 10% for most people. Individual metabolism varies based on genetics, muscle mass, hormones, and other factors. Use this as a starting point and adjust based on actual results over 2-4 weeks.
Should I eat back exercise calories?
If your activity level is already factored in, you generally don't need to eat back exercise calories. If you track exercise separately, eating back 50-75% of exercise calories is a common approach to avoid overestimating burns.