Applying a number format to a cell doesn’t change the value — only how the value appears in the worksheet. For example, if a cell contains 0.874543, you may format it to appear as 87%. If that cell is used in a formula, the formula uses the full value (0.874543), not the displayed value (87%).

In some situations, formatting may cause Excel to display calculation results that appear incorrect, such as when totaling numbers with decimal places. For example, if values are formatted to display two decimal places, you may not see the actual numbers used in the calculations. But because Excel uses the full precision of the values in its formula, the sum of the two values may appear to be incorrect. Several solutions to this problem are available. You can format the cells to display more decimal places. You can use the ROUND function on individual numbers and specify the number of decimal places

Excel should round to. Or you can instruct Excel to change the worksheet values to match their displayed format. To do so, access the Excel Options dialog box and click the Advanced tab. Check the Set Precision as Displayed check box (is located in the When Calculating This Workbook section).

Attention

Selecting the Precision as Displayed option changes the numbers in your worksheets to permanently match their appearance onscreen. This setting applies to all sheets in the active workbook. Most of the time, this option is not what you want. Make sure that you understand the consequences of using the Set Precision as Displayed option.