Excel provides different ways to calculate percentages. For example, you can use Excel to calculate sales tax for purchases, the percentage of correct answers on a test, or the percentage of change between two values.
Use the provided sample data and the following procedures to learn how to calculate percentages.
Calculate the percentage if you know the total and amount
Let's say that you answered 42 questions out of 50 correctly on a test. What is the percentage of correct answers?

Click any blank cell.

Type =42/50, and then press RETURN .
The result is 0.84.

Select the cell that contains the result from step 2.

On the Home tab, click Percent Style .
The result is 84%, which is the percentage of correct answers on the test.
Note: To change the number of decimal places that appear in the result, click Increase Decimal or Decrease Decimal .
Calculate the total if you know the amount and percentage
Let's say that the sale price of a shirt is $15, which is 25% off the original price. What is the original price? In this example, you want to find 75% of which number equals 15.

Click any blank cell.

Type =15/0.75, and then press RETURN .
The result is 20.

Select the cell that contains the result from step 2.

On the Home tab, click Accounting Number Format
The result is $20.00, which is the original price of the shirt.
Calculate the amount if you know the total and percentage
Let's say that want to purchase a computer for $800 and must pay an additional 8.9% in sales tax. How much do you have to pay for the sales tax? In this example, you want to find 8.9% of 800.

Click any blank cell.

Type =800*0.089, and then press RETURN .
The result is 71.2.

Select the cell that contains the result from step 2.

On the Home tab, click Accounting Number Format
The result is $71.20, which is the sales tax amount for the computer.
Calculate the difference between two numbers as a percentage
Let's say that your earnings are $2,342 in November and $2,500 in December. What is the percentage of change in your earnings between these two months? Then, if your earnings are $2,425 in January, what is the percentage of change in your earnings between December and January? You can calculate the difference by subtracting your new earnings from your original earnings, and then dividing the result by your original earnings.
Calculate a percentage of increase

Click any blank cell.

Type =(25002342)/2342, and then press RETURN .
The result is 0.06746.

Select the cell that contains the result from step 2.

On the Home tab, click Percent Style .
The result is 7%, which is the percentage of increase in earnings.
Calculate a percentage of decrease

Click any blank cell.

Type =(24252500)/2500, and then press RETURN .
The result is 0.03.

Select the cell that contains the result from step 2.

On the Home tab, click Percent Style .
The result is 3%, which is the percentage of decrease in earnings.
Increase or decrease a number by a percentage
Let's say that you spend an average of $113 on food each week, and you want to increase your weekly food expenditures by 25%. How much can you spend? Or, if you want to decrease your weekly food allowance of $113 by 25%, what is your new weekly allowance?
Increase a number by a percentage

Click any blank cell.

Type =113*(1+0.25), and then press RETURN .
The result is 141.25.

Select the cell that contains the result from step 2.

On the Home tab, click Accounting Number Format
The result is $141.25, which is a 25% increase in weekly food expenditures.
Decrease a number by a percentage

Click any blank cell.

Type =113*(10.25), and then press RETURN .
The result is 84.75.

Select the cell that contains the result from step 2.

On the Home tab, click Accounting Number Format
The result is $84.75, which is a 25% reduction in weekly food expenditures.