How Many Calories Should I Eat? The Complete Calorie Calculator Guide
Ask ten people how many calories they should eat and you will hear ten different numbers. The truth is that your number is personal — it depends on your age, gender, height, weight and how active you are. This guide explains the science behind daily calorie needs, gives you the exact equation dietitians use, and shows how to set targets for losing, maintaining or gaining weight.
BMR vs TDEE: The Two Numbers You Need
Your BMR (basal metabolic rate) is the energy your body burns at complete rest — just keeping your heart, brain and organs alive. Your TDEE (total daily energy expenditure) is BMR multiplied by your activity level: the real number of calories you burn on a typical day.
Maintaining your weight means eating at your TDEE. Our calorie calculator shows both numbers instantly.
The Mifflin-St Jeor Equation (the One Dietitians Trust)
- Men: BMR = 10 × weight(kg) + 6.25 × height(cm) − 5 × age + 5
- Women: BMR = 10 × weight(kg) + 6.25 × height(cm) − 5 × age − 161
- Then multiply by your activity factor: 1.2 (sedentary) to 1.9 (very active)
Studies rank Mifflin-St Jeor among the most accurate BMR formulas — and our calculator uses it, so no arithmetic required on your part.
How Many Calories to Lose Weight
A deficit of about 500 calories per day typically produces roughly 0.5 kg of weight loss per week. To lose weight, aim for maintenance minus 300–500 calories. Avoid going below roughly 1,200 (women) or 1,500 (men) per day without professional guidance.
How Many Calories to Gain Weight (or Muscle)
To gain weight, add a surplus of about 300–500 calories to maintenance and combine it with strength training so the surplus builds muscle rather than only fat. Protein should stay high — around 1.6–2.2 g per kg of body weight for those training seriously.
Myths About Daily Calories (Debunked)
- Myth: '2,000 calories is right for everyone' — Reality: your number depends on age, size and activity
- Myth: 'Eating at night makes you gain weight' — Reality: total daily calories matter more than timing
- Myth: 'All calories are equal' — Reality: protein and fiber affect hunger and metabolism differently
- Myth: 'The scale tells the whole story' — Reality: muscle gain can mask fat loss
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Frequently Asked Questions
Subtract about 300–500 calories from your maintenance number. A 500-calorie daily deficit yields roughly 0.5 kg per week.
BMR is your energy at complete rest; TDEE multiplies BMR by your activity level and is what you need to maintain weight.
Your TDEE. Enter your details in our calorie calculator and it shows your BMR and daily burn instantly.
It is one of the most accurate general BMR formulas available and is widely recommended by dietitians.