Calorie Calculator

The Calorie Calculator estimates your daily caloric needs based on your age, sex, height, weight, and activity level. Knowing how many calories you need helps you create a plan for weight loss, weight gain, or maintaining your current weight.

A calorie is a unit of energy. Your body burns calories through three main processes: Basal Metabolic Rate (BMR) — the calories burned just to keep your body alive (60–70% of total), the Thermic Effect of Food (TEF) — energy used to digest food (about 10%), and physical activity (20–30%). Your Total Daily Energy Expenditure (TDEE) is the sum of all three.

To lose weight, you need to consume fewer calories than your TDEE (caloric deficit). To gain weight, you need to consume more (caloric surplus). A deficit of about 500 calories per day leads to roughly 1 pound (0.45 kg) of weight loss per week, since 1 pound of body fat equals approximately 3,500 calories.

How the Formula Works

Uses the Mifflin-St Jeor equation: Men: BMR = 10 × weight(kg) + 6.25 × height(cm) − 5 × age − 161. Women: BMR = 10 × weight(kg) + 6.25 × height(cm) − 5 × age + 5. TDEE = BMR × Activity Factor.

• Step 1: Calculate BMR using the Mifflin-St Jeor equation
• Step 2: Multiply BMR by your activity level multiplier
• Sedentary (little or no exercise): BMR × 1.2
• Lightly active (1–3 days/week): BMR × 1.375
• Moderately active (3–5 days/week): BMR × 1.55
• Very active (6–7 days/week): BMR × 1.725
• Extra active (very hard exercise + physical job): BMR × 1.9

How to Use This Calculator

1. Enter your age, sex, weight, and height
2. Select your typical activity level
3. Click Calculate to see your daily calorie needs
4. View calorie targets for weight loss, maintenance, and weight gain

Tips & Best Practices

• Never go below 1,200 calories/day (women) or 1,500 calories/day (men) without medical supervision
• Aim for 1–2 pounds of weight loss per week for sustainable results
• Track your food intake for at least a week to understand your actual calorie consumption
• Protein-rich foods keep you fuller longer and help preserve muscle during weight loss
• Your calorie needs decrease as you lose weight — recalculate every 10–15 lbs lost

Important Limitations

• Calorie formulas provide estimates — individual metabolism varies by 5–15%
• Does not account for medical conditions affecting metabolism (thyroid disorders, etc.)
• Activity level is self-reported and often overestimated
• Muscle mass significantly affects calorie burn but isn't captured in basic formulas