How to Calculate Calories Burned in a Day

Karen Frazier
Woman weighing caloric content of foods
Do all calories burn equally?

How many calories burned in a day? The answer depends on a large number of individual factors. There are many aspects of your life and health that make a unique determination for your body of how many calories burned in a day.

Factors Affecting Calories Burned in a Day

The number of calories burned in a day by your body depends on many factors unique to the individual. Everyone's body is different and responds to a variety of things. In general, it is possible to calculate the amount of calories burned daily based on averages taken from a large sample size of the population. Some of the factors that affect how many calories your body burns on a daily basis follow.

Activity Level

The more active you are, the more calories you burn. Activity level consists of how much exercise you get and how active or sedentary you are in your job. It also includes whether you primarily stand, sit, or lie down during the day and whether or not you fidget or sit still.

Body Composition

Many people are surprised to learn body composition plays a role in how many calories your body burns. Lean tissue - specifically muscle - has more caloric requirements than body fat. This is one reason why men typically have higher caloric needs than women - because their bodies tend to have a larger amount of muscle naturally, while women's bodies tend to have a higher body fat percentage.

The Foods You Eat

To some extent, the foods you eat may affect your body's caloric requirements. While many experts believe a calorie is a calorie and if you eat fewer calories than you burn, you will lose weight; other experts are beginning to question the conventional wisdom that all calories are created equal. For some people, it appears all calories are not created equal. In some cases, empty calories in the form of sugar and simple carbohydrates may be processed differently by the body. A number of people on low carbohydrate diets such as the Atkins Diet and the American Diabetic Diet have found they can eat a few more calories, if they leave out sugars. Regardless of whether this is true for you or not, empty calories contained in sugars and simple carbohydrates like white flour don't bring anything to your diet nutritionally and are always best when kept at a minimum.

Other Factors

A number of other factors may affect how many calories your body burns, as well. These are mostly related to your body's unique makeup and include:

  • Thyroid disease
  • Stress levels
  • Amount of sleep you get
  • Body chemistry issues such as cortisol
  • Genetics

Calculating Caloric Needs

With all of the factors that makeup your body's individual needs, is it possible to calculate how many calories your body burns in a day? The answer is a qualified yes. Science has created formulas that allow you to calculate a general number of calories your body burns daily. These formulas are based on averages taken from large samples of people. Using them, you can come close to calculating how many calories your body burns on a daily basis.

Basal Metabolic Rate (BMR)

Your basal metabolic rate is an average based on a large sampling of people. It calculates the minimum number of calories your body most likely needs to sustain bodily functions such as breathing and circulation. You can calculate your basal metabolic rate using a BMR calculator; however, it is important to note your BMR is the minimum number of calories your body needs to sustain its life functions. You should never eat fewer calories than this number in an attempt to lose weight unless directed to do so by a qualified physician.

Harris Benedict Equation

Using the Harris Benedict equation allows you to achieve a general number that tells you approximately how many calories your body burns daily based on your activity level. In order to use the Harris Benedict equation, you will need to calculate your BMR and then take a really honest look at how active you are on a daily basis. The Harris Benedict equation then supplies you with a multiplier based upon your self-assessed activity level that tells you approximately how many calories your body burns on a daily bases based upon those activity levels.

What Does it All Mean?

Now that you've calculated your BMR and know approximately how many calories your body burns on a daily basis, you can take these numbers and use them as a way to custom tailor your own weight loss program. By counting calories each day, you can make sure you eat enough calories to sustain your body's basic functions while still providing your body with a caloric deficit required to lose weight. Generally, it is recommended that you take your Harris Benedict number and eat between 200 and 500 fewer calories daily than calculated in order to lose weight, making sure that you never eat fewer calories than your BMR requires.

Knowing both of these numbers can help you to either lose weight or maintain your weight loss. The numbers can also help you to set up a personalized program of diet and exercise to help you meet your weight loss goals.

How to Calculate Calories Burned in a Day