Microsoft Excel simplifies complex or repetitive calculations by allowing you to create customized spreadsheets and format them as necessary. Because Excel's primary feature is dealing with numbers, the program offers many numeric formatting options, such as percentages, decimals and currency. Although you numerically convert a percentage into decimal format by dividing by 100, this is unnecessary in Excel. You need only define the format, and Excel automatically performs the calculation.
Right-click the cell you wish to change, and select "Format Cells."
Click the "Number" tab in the Format Cells window.
Click "Number" in the category list.
Enter the number of decimal places you prefer next to the field labeled Decimal Places. This can be done by manually entering the number or by clicking the up/down arrows to change the default value of 2.
Click "OK" to change the percent into a decimal.