How Do I Calculate My Calories?

Reviewed on 9/21/2021
There are different ways to calculate the calories you need every day in order to maintain a healthy weight, which include your basal metabolic rate (BMR), physical activity, and the thermic effect of food. The number of calories you need is based on your age, weight, height, gender, and physical activity.
There are different ways to calculate the calories you need every day in order to maintain a healthy weight, which include your basal metabolic rate (BMR), physical activity, and the thermic effect of food. The number of calories you need is based on your age, weight, height, gender, and physical activity.

The “percent of daily values” featured on food nutrition labels is based on an average person eating 2,000 calories per day. But most people will require more or fewer than 2,000 calories to maintain a healthy weight. 

The number of calories an individual needs is based on:

  • Age
  • Weight 
  • Height
  • Gender 
  • Physical activity

There are different ways to calculate the calories you need to maintain a healthy weight: basal metabolic rate (BMR), physical activity, and the thermic effect of food.

Basal Metabolic Rate (BMR) 

  • This is the number of calories (energy) a person’s body needs at rest
  • The BMR accounts for about 60 to 70 percent of calories burned in a day
  • To calculate BMR, there are different formulas, as shown in the table below.
  • There are also online BMR calculators where you can enter your weight, height, age, and gender and it will calculate BMR for you.
How to Calculate Basal Metabolic Rate (BMR)
Harris-Benedict Formula Mifflin-St Jeor Formula
Adult males: 66 + (6.3 x body weight in lbs.) + (12.9 x height in inches) – (6.8 x age in years) = BMR Adult males: (9.99 × weight [kg]) + (6.25 × height [cm]) – (4.92 × age [years]) + 5 = BMR
Adult females: 655 + (4.3 x weight in lbs.) + (4.7 x height in inches) – (4.7 x age in years) = BMR Adult females: (9.99 × weight [kg]) + (6.25 × height [cm]) − (4.92 × age [years]) – 161 = BMR

Physical Activity 

Once you have calculated your BMR, you can take into account your level of physical activity to determine your daily caloric needs to maintain your current weight

  • Sedentary (little or no exercise): BMR x 1.2 = daily calories needed
  • Lightly active (light exercise/sports 1-3 days/week): BMR x 1.375 = daily calories needed
  • Moderately active (moderate exercise/sports 3-5 days/week): BMR x 1.55 = daily calories needed
  • Very active (hard exercise/sports 6-7 days a week): BMR x 1.725 = daily calories needed
  • Extra active (very hard exercise/sports and physical job): BMR x 1.9 = daily calories needed

Depending upon the above calculation:

  • To maintain your current weight, eat the same number of calories you burn 
  • For weight loss, you need to eat fewer calories than you burn 
  • For weight gain, you need to eat more calories than you burn 

Thermic Effect of Food 

  • This refers to the energy the body needs to digest, absorb, metabolize, store, and dispose of food
  • The thermic effect of foods may be increased by:
    • Larger meal sizes (as opposed to frequent small meals)
    • Intake of carbohydrate and protein (as opposed to dietary fat)
    • Low-fat plant-based diets

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Reviewed on 9/21/2021
References
https://www.checkyourhealth.org/eat-healthy/cal_calculator.php

https://www.thecalculatorsite.com/articles/health/bmr-formula.php

https://pubmed.ncbi.nlm.nih.gov/31021710/