CalcPad

Calorie Calculator

Estimate your daily calorie needs based on age, weight, height, gender, and activity level using the Mifflin-St Jeor equation.

kg

Your current body weight in kilograms.

cm

Your height in centimeters.

years

Your current age in years.

Biological sex, used in the BMR calculation.

How active you are on a typical week.

Understanding Basal Metabolic Rate and TDEE

Your Basal Metabolic Rate (BMR) is the number of calories your body burns at complete rest just to maintain basic life functions like breathing, circulation, and cell production. BMR accounts for roughly 60-75% of the calories most people burn each day.

Your Total Daily Energy Expenditure (TDEE), also called maintenance calories, is your BMR multiplied by an activity factor. TDEE represents the total number of calories you burn in a day, including physical activity and the thermic effect of food (the energy used to digest meals).

To maintain your current weight, you need to consume approximately your TDEE in calories. To lose weight, eat fewer calories than your TDEE. To gain weight, eat more. A deficit or surplus of about 500 calories per day results in roughly 0.5 kg (1 pound) of weight change per week.

The Mifflin-St Jeor Equation

This calculator uses the Mifflin-St Jeor equation, which is considered the most accurate BMR formula for most people. Published in 1990, it has been validated in numerous studies and is recommended by the Academy of Nutrition and Dietetics.

The formulas are:

  • 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

The BMR is then multiplied by an activity factor to estimate TDEE:

  • Sedentary: BMR x 1.2
  • Lightly active: BMR x 1.375
  • Moderately active: BMR x 1.55
  • Very active: BMR x 1.725
  • Extra active: BMR x 1.9

Keep in mind that all calorie calculators provide estimates. Individual metabolism varies based on genetics, muscle mass, hormones, and other factors. Use the results as a starting point and adjust based on real-world results over 2-4 weeks.

Using Calorie Targets for Weight Management

For safe and sustainable weight loss, most health professionals recommend a moderate calorie deficit of 250-500 calories per day below maintenance. This produces a weight loss rate of 0.25 to 0.5 kg per week.

Larger deficits can lead to faster weight loss but often result in muscle loss, nutrient deficiencies, metabolic adaptation, and are harder to maintain long-term. Very low calorie diets (under 1,200 for women or 1,500 for men) should only be followed under medical supervision.

For weight gain, a surplus of 250-500 calories per day is recommended. Combined with resistance training, this surplus supports muscle growth while minimizing fat gain. Without exercise, excess calories are more likely to be stored as fat.

Regardless of your goal, protein intake matters. Aim for 1.6-2.2 grams of protein per kilogram of body weight per day to support muscle maintenance during weight loss or muscle growth during a surplus.

Frequently Asked Questions

How accurate is this calorie calculator?
The Mifflin-St Jeor equation is accurate to within about 10% for most people. Individual variation in metabolism means the estimate may be slightly high or low for you. Use the result as a starting point, track your weight for 2-4 weeks, and adjust your intake by 100-200 calories if you are not seeing the expected results.
What activity level should I choose?
Be honest about your typical week. Sedentary means a desk job with no regular exercise. Lightly active means light exercise or walking 1-3 days per week. Moderately active means structured exercise 3-5 days per week. Very active means intense exercise 6-7 days per week. Extra active is reserved for athletes training multiple hours daily or people with very physically demanding jobs.
Should I eat back the calories I burn during exercise?
The activity multiplier already accounts for your general exercise level, so you do not need to add extra calories for regular workouts. However, if you do an unusually intense or long workout beyond your normal routine, eating back about half of those extra calories is a reasonable approach. Be cautious with calorie burn estimates from fitness trackers, as they tend to overestimate by 30-90%.
Why do men and women have different calorie needs?
On average, men have more muscle mass and less body fat than women of the same height and weight. Muscle tissue is more metabolically active than fat tissue, meaning it burns more calories at rest. This is why the Mifflin-St Jeor equation has a different constant for men (+5) and women (-161), resulting in a higher BMR estimate for men.

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