Daily Calorie Calculator

How Daily Calorie Calculation Works

Your daily calorie needs depend on several factors: your Basal Metabolic Rate (BMR), activity level, and weight goals. Our calculator uses the scientifically-backed Mifflin-St Jeor equation to calculate your BMR, then multiplies it by an activity factor to determine your Total Daily Energy Expenditure (TDEE).

Understanding your calorie needs is fundamental for weight management, whether you want to lose, gain, or maintain weight. By consuming the right amount of calories for your goals, you can achieve and maintain a healthy weight while ensuring your body gets the energy it needs.

Calorie Calculation Formula

Step 1: Calculate BMR

Using 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

Step 2: Apply Activity Factor


Sedentary (little/no exercise): BMR × 1.2
Lightly active (light exercise 1-3 days/week): BMR × 1.375
Moderately active (moderate exercise 3-5 days/week): BMR × 1.55
Very active (hard exercise 6-7 days/week): BMR × 1.725
Super active (very hard exercise, physical job): BMR × 1.9

Step 3: Adjust for Goals


Maintain weight: TDEE
Lose 0.5 lbs/week: TDEE - 250 calories
Lose 1 lb/week: TDEE - 500 calories
Lose 2 lbs/week: TDEE - 1000 calories
Gain 0.5 lbs/week: TDEE + 250 calories
Gain 1 lb/week: TDEE + 500 calories

Examples

Example 1: Weight Maintenance

Profile: 30-year-old female, 65 kg, 165 cm, moderately active

BMR: (10 × 65) + (6.25 × 165) - (5 × 30) - 161 = 1,384 calories

TDEE: 1,384 × 1.55 = 2,145 calories/day

Goal: Maintain weight = 2,145 calories/day

Example 2: Weight Loss

Profile: 25-year-old male, 80 kg, 175 cm, lightly active

BMR: (10 × 80) + (6.25 × 175) - (5 × 25) + 5 = 1,675 calories

TDEE: 1,675 × 1.375 = 2,303 calories/day

Goal: Lose 1 lb/week = 2,303 - 500 = 1,803 calories/day

Example 3: Weight Gain

Profile: 22-year-old male, 60 kg, 170 cm, very active

BMR: (10 × 60) + (6.25 × 170) - (5 × 22) + 5 = 1,557 calories

TDEE: 1,557 × 1.725 = 2,686 calories/day

Goal: Gain 1 lb/week = 2,686 + 500 = 3,186 calories/day

Frequently Asked Questions

How accurate is this calorie calculator?
Our calculator uses the most accurate available equations for the general population. However, individual metabolic rates can vary by ±10-15%. Factors like genetics, body composition, medical conditions, and medications can affect your actual calorie needs.
Should I eat exactly the calculated calories every day?
Use the calculation as a starting point and adjust based on your results over 2-3 weeks. If you're not seeing expected changes, adjust your intake by 100-200 calories and monitor your progress. Consistency over time is more important than daily precision.
What's the minimum number of calories I should eat?
Generally, women shouldn't go below 1,200 calories/day and men shouldn't go below 1,500 calories/day without medical supervision. Very low-calorie diets can slow metabolism, cause nutrient deficiencies, and lead to muscle loss.
How do I choose the right activity level?
Be honest about your overall activity, not just formal exercise. Include your job activity, daily movement, and exercise. If you sit most of the day and exercise 3 times a week, "lightly active" is probably more accurate than "moderately active."
Should I recalculate as I lose/gain weight?
Yes, your calorie needs change as your weight changes. Recalculate every 10-15 pounds of weight change or if your progress stalls for 2-3 weeks. Your metabolism adapts, so adjustments are normal and necessary.

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