Calorie Calculator
Find out how many calories your body needs each day for weight maintenance, loss, or gain.
Calories are the energy your body uses for everything from breathing and digesting food to walking and lifting weights. Your daily calorie needs depend on your age, sex, weight, height, and how active you are. This calculator estimates your needs using the Mifflin-St Jeor equation, widely considered the most accurate BMR formula for the general population.
Once you know your maintenance calories, you can adjust your intake to match your goal. For fat loss, a deficit of 300-500 calories per day is sustainable for most people. For muscle gain, a surplus of 200-400 calories above maintenance, combined with progressive resistance training, supports lean mass growth without excessive fat gain. For maintenance, simply eat at your calculated number.
Calories from different sources affect your body differently. Pair this calculator with our Macro Calculator to dial in your protein, carb, and fat ratios, and the Protein Calculator to ensure you meet your muscle-supporting protein needs.
How Calories Are Calculated
This calculator uses the Mifflin-St Jeor equation, the most accurate BMR formula for the general population:
- Male: BMR = 10 x weight(kg) + 6.25 x height(cm) - 5 x age + 5
- Female: BMR = 10 x weight(kg) + 6.25 x height(cm) - 5 x age - 161
Total Daily Energy Expenditure (TDEE) is your BMR multiplied by your activity level. A deficit of 500 calories/day yields ~1 lb of fat loss per week. A surplus of 250-500 calories/day supports muscle gain with minimal fat gain.
Related: Use our TDEE Calculator for detailed macronutrient breakdowns. Also see our Calorie Deficit Guide.
Frequently Asked Questions
How many calories should I eat to lose weight?
A deficit of 300-500 calories below your maintenance is safe and sustainable for weight loss of 0.5-1 lb per week. A larger deficit may lead to muscle loss.
How many calories should I eat to gain muscle?
A surplus of 200-300 calories above maintenance combined with resistance training supports muscle gain. Focus on 1.6-2.2 g of protein per kg of body weight.
What happens if I eat too few calories?
Eating too few calories (below 1200 for women or 1500 for men) can slow metabolism, cause muscle loss, trigger nutrient deficiencies, and disrupt hormones.
Do I need to track calories forever?
No. Tracking for 2-4 weeks helps you understand portion sizes. Many people maintain results with intuitive eating after that.