How to Convert Grams to Calories

Last Updated: November 1, 2022 References

Learning how to count calories is a great way to help you achieve a healthy diet. While most food labels list the number of calories contained in their products, they oftentimes do not list the breakdown of which specific nutrients those calories come from. By understanding the difference between calories and grams, and learning the conversion rate, you can easily calculate how many calories are in specific nutrients.

Method 1

Method 1 of 3:

Converting Fat Grams to Calories

1
Look at the nutrition label. Most food labels will list how many grams of fat there are for each serving of that specific product. This is how you will calculate the calories.^{[1]
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Trustworthy Source
EatRight.org
Organization associated with the Academy of Nutrition and Dietetics providing advice about food, health, and fitness
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2
Multiply the fat grams by nine. Every gram of fat contains nine calories.^{[2]
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Trustworthy Source
Cleveland Clinic
Educational website from one of the world's leading hospitals
Go to source} To figure out how many calories there are in the fat content, simply multiple the fat grams by nine.^{[3]
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Research source}
- For example, if there are ten grams of fat, you would multiple ten grams of fat by nine calories, for a total of 90 calories. This is how many calories there are in the fat grams.
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3
Calculate how many calories there are in the entire product. To figure out how many total calories there are in the fat content of a product, multiply the original number you received before, by the amount of servings there are on the label.^{[4]
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Trustworthy Source
US Food and Drug Administration
U.S. government agency responsible for promoting public health
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- If a label states there are three servings, you would then multiply 90 by three, for a total of 270 calories.

Method 2

Method 2 of 3:

Converting Grams of Carbohydrates and Proteins to Calories

1
Know that a carbohydrate is an organic compound. Carbohydrates are made of carbon, hydrogen, and oxygen. They always contain calories (4 per gram), but calories do not automatically mean there are carbohydrates, because calories are in other macro-nutrients.^{[5]
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2
Check the nutrition label. You will see how many grams of carbohydrates there are per serving. Carbohydrates have four calories per gram. Multiply the number of carbohydrates by four to figure out how many calories there are.^{[6]
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- For example, if a product had nine grams of carbohydrates, you would use the equation (9 x 4) to get a total of 36 calories. You would use four as your multiplier because there are four calories in every one gram of carbohydrate.
3
Find out the number of calories that come from protein. Proteins are also listed in grams on food labels. Just like carbohydrates, protein carries four calories per gram. Again, multiply the number of protein grams by four to receive the number of calories.^{[7]
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Method 3

Method 3 of 3:

Understanding Grams vs. Calories

1
Realize the difference between a gram and a calorie. A gram is a metric unit of weight that is equal to one thousandth of a kilogram.^{[8]
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Research source} A calorie is a unit of energy that people receive from food. One pound of body fat is equal to about 3500 calories.
- A gram and a calorie are different units of measure that can't be converted into one another.^{[9]
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  Research source}
2
Find out for which energy source you want to measure the calories. The quantity of calories per gram of food is dependent upon its ratio of macro-nutrients. The human body can derive energy (employ calories) from three main macro-nutrients: carbohydrates, fats, and proteins.^{[10]
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Trustworthy Source
Cleveland Clinic
Educational website from one of the world's leading hospitals
Go to source}
- You can't weigh food and convert the grams into calories. You have to know how many calories there are in a specific type of macro-nutrient gram to calculate the total calories in it.
3
Multiply the number of grams by the conversion number. Look on the label of the food your want to calculate the calories for. Each nutrient will be listed in grams. Once you find the one you are looking for, you can multiply that number by the number of calories that specific nutrient has in each gram.^{[11]
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Trustworthy Source
American Heart Association
Leading nonprofit that funds medical research and public education
Go to source}

Community Q&A

Question

How many calories are in 71 grams of sugar?

Purplecakecaroline

Community Answer

There are 274.77 calories in 71 grams of sugar. There are 3.87 calories in one gram of sugar, so to calculate the number of calories in 71 grams of sugar, multiply 3.87 and 71.
Question

How do I convert sugar grams into calories?

Scintillacatelepsy

Community Answer

One gram of sugar contains 3.87 calories, so multiply the grams of sugar by 3.87 (or just 4 if you're not looking to be that precise).
Question

How do I find out the amount of calories in a package of food?

Community Answer

Most packaged foods have nutrition facts on them. Look for a white rectangle with black text on it. Usually it will be on the back of a package of food or the side, if it is a box. There is a lot of information but calories is usually near the top.