How to Calculate Percentages in Excel



Two Percentage Calculation Types

This page describes how to calculate a percentage in Excel, either as a percentage proportion or as a percentage change.

Examples of these two percentage types are:

Percentage as
a Proportion
E.g. if, out of 120 questions, you answer 90 correctly, how is this expressed as a percentage score?
Percentage
Change
E.g. if your sales figures are $1,250 in January and $1,750 in February, what is the percentage increase in February, compared to January?

The two percentage calculations are explained below.



How to Calculate a Percentage as a Proportion

If you want to calculate a sample of a set, as a percentage, this is done by dividing the sample size by the size of the full set.

For example, if you take an exam and answer 90 out of 120 questions correctly, this can be expressed as a percentage by simply dividing 90 by 120. This gives the result 0.75, or 75%

This percentage calculation is shown in the Excel spreadsheet below.

 Formulas:

 AB
1Correct Answers:90
2Total Questions:120
3Percentage Score:=B1 / B2

 Results:

 AB
1Correct Answers:90
2Total Questions:120
3Percentage Score:75%

Note that, to get the result shown as a percentage, as in the above 'Results' spreadsheet, it is necessary to set cell B3 to have percentage formatting.



How to Calculate Percentage Change

If you want to calculate the percentage change between value a and value b, this is done using the formula:

percentage change = ( b - a ) / a

For example if your sales figures are $1,250 in January and $1,750 in February, the percentage change in February, compared to January, is given by:

percentage change = ( $1,750 - $1,250 ) / $1,250

This gives the result 0.4, or +40%

This percentage calculation is shown in the Excel spreadsheet below.

 Formulas:

 AB
1Jan Sales Figure:$12,500
2Feb Sales Figure:$17,500
3% Change:=(B2 - B1) / B1

 Results:

 AB
1Jan Sales Figure:$12,500
2Feb Sales Figure:$17,500
3% Change:40.0%

As in the previous example, in order to get the result displayed as a percentage, it is necessary to set cell B3 to have percentage formatting.



Formatting to Display Percentages in Excel Cells

Percentages in Excel are stored as decimal values. For example, 25% is stored as the value 0.25, 50% is stored as the value 0.5, etc.

It is only the formatting of a cell that makes the underlying decimal value appear as a percentage.

Excel Format Cells Percentage Option

To change a cell's formatting to display percentages:

  • Select the cell(s) to be formatted
  • Right click on the selected cells, and from this menu, select the Format Cells ... option
  • The 'Format Cells' window (shown aboveon the right) will appear. Make sure the Number tab is selected and from within the options in this tab, select Percentage
  • An option will appear in the Format Cells box, that allows you to select how many decimal places you want to display
  • Click OK

The result of formatting (with zero decimal places) is shown below.

 Values Displayed as Decimals:

 AB
10.5 
20.75 

 After Formatting as a Percentage:

 AB
150% 
275% 

Further examples of Calculating Percentages in Excel can be found on the Microsoft Office website.