Percentages can be frustrating at times because it’s not always easy to recall what we learned in school. Allow Excel to do the work for you; for example, simple formulas can help you calculate percentage of a total or the percentage difference between two numbers.

**Find the percentage of a total**

Assume you answered 43 of 50 questions correctly on a test. How many correct answers are there?

- Click any blank cell.
- Type
**=43/50**, and then press ENTER .

The result is 0.86. - Select the cell that contains the result from step 2.
- On the
**Home**tab, click the percentage button .

The percentage of correct answers on the test is 86.00% as a result.

**Note:** To change the number of decimal places that appear in the result, click **Increase Decimal** or **Decrease Decimal** .

## Determine the percentage difference between two numbers.

Assume your November earnings are $1,332 and your December earnings are $2,700. What is the difference in your earnings between these two months? Then, if your earnings in January are $2,430, what is the percentage change in earnings between December and January? The difference can be calculated by subtracting your new earnings from your original earnings and then dividing the result by your original earnings.

### Calculate percentage increase.

- Click any blank cell.
- Type
**=(2700-1332)/1332**, and then press RETURN .

The result is 1.02703 - Select the cell that contains the result from step 2.
- On the
**Home**tab, click .

The result is 102.70%, which is the percentage of increase in earnings.

**Note:** To change the number of decimal places that appear in the result, click **Increase Decimal** or **Decrease Decimal** .

### Calculate percentage decrease.

- Click any blank cell.
- Type
**=(2430-2500)/2500**, and then press ENTER .

The result is -0.028. - Select the cell that contains the result from step 2.
- On the
**Home**tab, click .

The result is -2.80%, which is the percentage of decrease in earnings.

**Note:** To change the number of decimal places that appear in the result, click **Increase Decimal** or **Decrease Decimal** .

## When you have the amount and percentage, find the total.

Assume a shirt is on sale for $15, which is 25% off the original price. What was the original cost? In this case, you want to find 75% of a number that 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.
**In newer versions:**On the**Home**tab, click .

The result is $20.00, which is the original price of the shirt.

**In Excel for Mac 2011:**On the

**Home**tab, under

**Number**, click

**Currency**

The result is $20.00, which is the original price of the shirt.

**Note:** To change the number of decimal places that appear in the result, click **Increase Decimal** or **Decrease Decimal** .

## When you know the total and percentage, find an amount.

Assume you want to buy a computer for $800 but must pay an additional 8.9% in sales tax. How much sales tax do you have to pay? In this case, you’re looking for 8.9% of 800.

- Click any blank cell.
- Type
**=800*0.089**, and then press ENTER.

The result is 71.2. - Select the cell that contains the result from step 2.
**In newer versions:**On the**Home**tab, click .

**In Excel for Mac 2011:**On the

**Home**tab, under

**Number**, click

**Currency**

The result is $71.20, which is the sales tax amount for the computer.

**Note:** To change the number of decimal places that appear in the result, click **Increase Decimal** or **Decrease Decimal** .

## A number can be increased or decreased by a percentage.

Assume you spend an average of $113 per week on food and want to increase your weekly food expenditures by 25%. How much money do you have? What is your new weekly allowance if you want to reduce your weekly food allowance of $113 by 25%?

### Increase the number by a certain percentage.

- Click any blank cell.
- Type
**=113*(1+0.25)**, and then press ENTER.

The result is 141.25. - Select the cell that contains the result from step 2.
**In newer versions:**On the**Home**tab, click .

**In Excel for Mac 2011:**On the

**Home**tab, under

**Number**, click

**Currency**

The result is $141.25, which is a 25% increase in weekly food expenditures.

**Note:** To change the number of decimal places that appear in the result, click **Increase Decimal** or **Decrease Decimal** .

### Decrease the number by a certain percentage.

- Click any blank cell.
- Type
**=113*(1-0.25)**, and then press ENTER .

The result is 84.75. - Select the cell that contains the result from step 2.
**In newer versions:**On the**Home**tab, click .**In Excel for Mac 2011:**On the**Home**tab, under**Number**, click**Currency**

The result is $84.75, which is a 25% reduction in weekly food expenditures.

**Note:** To change the number of decimal places that appear in the result, click **Increase Decimal** or **Decrease Decimal** .

**Note:** To change the number of decimal places that appear in the result, click **Increase Decimal** or **Decrease Decimal** .

### Decrease the number by a certain percentage.

- Click any blank cell.
- Type
**=113*(1-0.25)**, and then press ENTER .

The result is 84.75. - Select the cell that contains the result from step 2.
**In newer versions:**On the**Home**tab, click .**In Excel for Mac 2011:**On the**Home**tab, under**Number**, click**Currency**

The result is $84.75, which is a 25% reduction in weekly food expenditures.

**Note:** To change the number of decimal places that appear in the result, click **Increase Decimal** or **Decrease Decimal** .