How to Calculate Fat Calories

Co-authored by Courtney Fose, RD, MS

Last Updated: March 13, 2023

Calories are a unit of measurement that show how much energy a food item will provide to your body. Calculating fat calories will benefit you when you want to calculate how many calories you need to eat to lose or gain weight. You will just need to have the nutrition information for the food you want to calculate fat calories. A calculator is also helpful for finding the calories from fat.

Method 1

Method 1 of 2:

Calculating Calories from Fat in Food

1
Read the nutrition panel on the food package. The nutrition panel on food packages has all of the information that you will need to calculate calories from fat. The panel is black and white and it should say “Nutrition Facts” at the top of it.^{[1]
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Research source} Find this panel and then find the number of fat grams per serving.
- Write down how many grams of fat are in this food. For example, if the food has 3.4 grams of fat in it, then write this number down.
- In some cases, the nutrition panel will also provide a number for the calories from fat. If your panel has this information listed, then you will not need to calculate any further unless you want to find the percentage.
- If there is no nutrition panel, then you can try to search for the nutrition information. Try visiting the product’s website if the item is prepackaged. If you got the item in a restaurant, then check the restaurant’s nutrition information. If the item was homemade, then try checking recipe websites for the nutrition information of similar recipes.
2
Multiply the number fat grams by 9. To get the number of calories from fat using the fat grams, you will just need to multiply the total fat grams per serving by 9. This is because one gram of fat contains 9 calories.^{[2]
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- For example, if the food has 3.4 grams of fat, then your equation might look like 3.4 X 9 = 30.6. This food would have 30.6 calories from fat.
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3
Convert the calories from fat to a percentage. After you have calculated the number of calories in the food that are from fat, you can convert this number to a percentage. To get the percentage of calories from fat in a food, just divide the number of calories from fat in one serving by the total number of calories in one serving.^{[3]
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Research source}
- For example, if the food has 260 calories in a serving and 30.6 calories from fat, then your equation might look like 30.6 / 260 = 0.1176
- To turn this result into a percentage, just move the decimal two spots to the right or multiply your result by 100. For example, 0.1176 X 100 = 11.76% or about 12%. This means that the food has a fat percentage of about 12%.

Method 2

Method 2 of 2:

Determining How Many Calories from Fat to Eat

1
Find out how many calories you need each day. The number of calories that you need on a daily basis will vary depending on your age, sex, and activity level. For example, a 20 year old male who exercises regularly will require more daily calories than a 40 year old male who has a sedentary lifestyle.^{[4]
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Trustworthy Source
University of Rochester Medical Center
Leading academic medical center in the U.S. focused on clinical care and research
Go to source}
- Consider your activity level, age, and sex to determine how many daily calories your need.
- Try using an online calculator to determine your calorie needs. You can also ask your doctor or a dietitian.
- There are also charts that you can consult for a rough estimate. These charts give an approximate number. For example, a woman between the ages of 31 and 50 who is moderately active needs 2,000 calories according to a chart provided by the University of Rochester Medical Center.^{[5]
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  Trustworthy Source
  University of Rochester Medical Center
  Leading academic medical center in the U.S. focused on clinical care and research
  Go to source}
2
Determine the percentage of fat you need in your diet. The percentage of your daily calories that should come from fat may vary depending on your goals. However, keep in mind that the ideal percentage is between 20% and 35%.^{[6]
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Mayo Clinic
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- If you are trying to lose weight or if your doctor has recommended a low-fat diet, then you may require a lower fat diet, such as 20% or 25% fat calories.
- If you are trying to gain weight, then you may require a higher fat diet, such as 30% or 35%.
3
Multiply your total calories by a fat calories percentage. To get the number of calories from fat you can consume each day, you will need to multiply your total daily calorie limit by the percentage of fat calories that you can eat every day.^{[7]
X
Trustworthy Source
University of Rochester Medical Center
Leading academic medical center in the U.S. focused on clinical care and research
Go to source} Convert your percentage into a decimal for the equation by placing a decimal in front of it before you calculate.
- For example, if you want 25% of your calories to come from fat, then you would use the decimal 0.25 in your equation. If you want 30% of your calories to come from fat, then you would use the decimal 0.30 in your equation.
- A sample equation might look something like 2,000 X 0.25 = 500. In this example, your total calories from fat would be 500.
4
Divide your result by 9. To get the number of fat grams that you can consume every day to stay within your limit, you will need to divide your total calories from fat result by 9. There are 9 calories in every gram of fat, so dividing by this number will give you a fairly accurate result.^{[8]
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Trustworthy Source
University of Rochester Medical Center
Leading academic medical center in the U.S. focused on clinical care and research
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- A sample equation might look like 500 / 9 = 55.5. In this example, your total fat gram limit would be 55.5 grams.