Shading Based on Odds and Evens

If you have a series of values in a range of cells, you might want to use different formatting to differentiate the odd numbers from the even numbers. The way you do this is through the use of the Conditional Formatting feature in Excel. Follow these steps:

1. Select the cells that contain the odd and even values.
2. Choose Conditional Formatting from the Format menu. Excel displays the Conditional Formatting dialog box.
3. Using the left-most drop-down list, choose Formula Is. (See Figure 1.)



Figure 1. The Conditional Formatting dialog box.

4. In the formula area, enter =MOD(A1,2)=1. This formula will return True if the cell contains an odd value.
5. Click on Format and change the format to reflect the formatting you want applied for cells containing odd values.
6. In the Conditional Formatting dialog box, click the Add button.
7. Repeat steps 3 through 5 for the second condition, but use the formula =MOD(A1,2)=0. This condition returns True if the cell contains an even value.
8. Click on OK to apply the conditional formats to the cells.

With this conditional formatting applied, if the cell is odd it will be one color and if even it will be another. If the cell contains text, the cell will be uncolored, meaning it will have the color of the cell before you added the conditional formatting. The conditional formatting overrides any formatting you put on the cell, so even if you try to change the cell color via the toolbar, the conditional formatting takes precedence.

It is interesting to note that if you have the Analysis ToolPak enabled in Excel, you might be tempted to use the ISODD and ISEVEN functions in the conditional format. These functions cannot apparently be used with conditional formatting. If you try to do so, Excel generates an error that says, "You may not use references to other worksheets or workbooks for Conditional Formatting criteria." The best bet is to use the MOD function, as described above.

ExcelTips is your source for cost-effective Microsoft Excel training. This tip (2767) applies to Microsoft Excel 97, 2000, 2002, and 2003. You can find a version of this tip for the ribbon interface of Excel (Excel 2007 and later) here: Shading Based on Odds and Evens.