How Many Calories Should I Eat?

Your daily calorie needs depend on your age, sex, weight, height, activity level, and personal goals. The number of calories you should eat each day is determined by your Basal Metabolic Rate (BMR) -- the energy your body uses at rest -- multiplied by an activity factor to estimate your Total Daily Energy Expenditure (TDEE). This calculator uses the clinically validated Mifflin-St Jeor equation, widely considered the most accurate formula for estimating calorie needs in healthy adults.

Quick Answer

The average adult needs 1,600 to 3,000 calories per day depending on age, sex, and activity level. Women typically need 1,600-2,400 calories, while men need 2,000-3,000 calories daily. Use the calculator below to find your exact number based on your personal stats and goals.

🎯 Calculate Your Daily Calories

Your Personalized Results

-- BMR (cal/day)
-- TDEE (cal/day)
-- Recommended

Understanding Your Daily Calorie Needs

Knowing how many calories you should eat each day is the foundation of any nutrition plan. Whether your goal is weight loss, muscle building, or simply maintaining a healthy weight, understanding your energy balance is key.

What Is BMR?

Your Basal Metabolic Rate (BMR) is the number of calories your body needs to perform basic life-sustaining functions like breathing, circulation, and cell production. BMR accounts for about 60-75% of your total daily calorie burn. It varies based on your age, sex, weight, and height.

What Is TDEE?

Total Daily Energy Expenditure (TDEE) is your BMR multiplied by an activity factor. TDEE represents the total number of calories you burn in a day, including exercise and daily movement. To maintain your current weight, you should eat roughly the same number of calories as your TDEE.

The Mifflin-St Jeor Equation

This calculator uses the Mifflin-St Jeor equation, which research has shown to be the most reliable formula for estimating BMR in healthy individuals:

  • Men: BMR = (10 x weight in kg) + (6.25 x height in cm) - (5 x age) + 5
  • Women: BMR = (10 x weight in kg) + (6.25 x height in cm) - (5 x age) - 161

Factors That Affect Your Calorie Needs

  • Age: Metabolic rate naturally decreases with age, typically by 1-2% per decade after age 20.
  • Sex: Men generally have a higher BMR due to greater muscle mass.
  • Body composition: More muscle mass means a higher metabolic rate.
  • Activity level: Physical activity can increase your calorie needs by 20-100% above BMR.
  • Goals: Weight loss typically requires a 500-calorie daily deficit, while muscle gain requires a surplus.

How Many Calories to Lose Weight?

To lose approximately one pound per week, you need a daily calorie deficit of about 500 calories below your TDEE. A deficit of 1,000 calories per day can lead to roughly two pounds of weight loss per week, though deficits greater than 500 calories are generally not recommended without medical supervision.

How Many Calories to Gain Muscle?

Building muscle requires a caloric surplus of roughly 250-500 calories per day above your TDEE, combined with resistance training and adequate protein intake (0.7-1g per pound of body weight).

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