How To Figure Out How Many Calories You Should Eat Per Day

Determining your daily calorie intake needs is an important part of losing, maintaining or gaining weight. An online search will uncover many methods for calculating caloric needs, but according to registered dietitian Erin Palinski, the Harris-Benedict equation is the most accurate method. The equation takes into account your basal metabolic rate (BMR), a measure of the number of calories your body burns while at rest, as well as your weight, height, sex, age and activity level.

Step 1

Calculate your BMR using one of the following equations.

If you're a woman, use this equation:

655 + (4.35 x your weight in pounds) + (4.7 x your height in inches) -- (4.7 x your age in years) = BMR

If you're a man, use this equation:

66 + (6.23 x your weight in pounds) + (12.7 x your height in inches) -- (6.8 x your age in years) = BMR

Step 2

Determine your level of daily activity using the following list.

Sedentary: Little to no daily exercise

Lightly active: Light exercise or sports one to three days per week

Moderately active: Moderate exercise or sports three to five per days per week

Very active: Hard exercise or sports six to seven days per week

Extra active: Very hard exercise or sports plus a physically demanding job or twice-daily physical training

Step 3

Use your daily activity level and BMR to calculate your daily calorie needs with one of the following equations.

Sedentary: BMR x 1.2 = daily calorie needs

Lightly active: BMR x 1.375 = daily calorie needs

Moderately active: BMR x 1.55 = daily calorie needs

Very active: BMR x 1.725 = daily calorie needs

Extra active: BMR x 1.9 = daily calorie needs

For example, a 5-foot-5-inch woman who is 30 years old, weighs 145 lb. and is moderately active would calculate her daily calorie needs this way:

BMR= 655 + (4.35 x 145 lbs) + (4.7 x 65 inches) -- (4.7 x 30 years)

BMR = 1,450

BMR x activity factor for moderate activity (1.55)

1,450 x 1.55 = 2,247 calories/day

Tips and Warnings

To lose 1 lb. per week, subtract 500 calories from your daily calorie needs, as determined by the steps above. For example, if your daily calorie needs are 2,247 calories, eat 1,747 calories per day to lose 1 lb. per week. To gain 1 lb. per week, add 500 calories to your daily calorie needs, as determined by the steps above. For example, if your daily calorie needs are 2,247 calories, eat 2,747 calories per day to gain 1 lb. per week. Keeping a food journal can help you keep track of your daily calorie intake.
Consuming fewer than 1,200 calories per day when trying to lose weight may actually slow your metabolism and decrease your BMR over time.