Turbocharge Your Spreadsheets with Heat Map Formatting

Heat maps are a common data visualization technique that uses color to offer a sense of scale. In this article you'll see how Excel's Conditional Formatting feature can be used to create an instant heat map for showing a sense of scale within a column of numbers. The technique is simple, but there is a nuance you'll need to be aware of.

The steps involved in building a heat map are shown in the figure:

1. Click any single cell within the list. Users sometimes mistakenly select a column before sorting. Doing so can cause Excel to sort the column separate from the rest of the data in the list.
2. Activate Excel's Data menu.
3. Click the Sort Z-A command to sort the numbers from highest to lowest.
4. Select the numbers you wish to format. It's important to wait and select the numbers after you sort, otherwise the sort may not work correctly.
5. Choose Conditional Formatting from Excel's Home menu.
6. Choose Color Scales from within the Conditional Formatting menu.
7. Choose a color scheme. Excel offers a live preview as you hover over each scheme, so you'll be able to see the impact before you commit to it.
8. If you've sorted the numbers in descending order, you'll have a heat map. Conditional Formatting will still work if you didn't sort the numbers, but you'll have a scattered array of colors as opposed to a smooth transition.

The Color Scales Conditional Format requires numbers, and unfortunately cannot be applied to entire rows if some columns contain text. It is possible, however, to manually create conditional formatting rules for such instances.

If you change your mind about applying conditional formatting, either click Undo immediately after you apply the formatting, or:

1. Choose Conditional Formatting from Excel's Home menu.
2. Choose Clear Rules.
3. Choose between Clear Rules from Selected Cells and Clear Rules from Entire Sheet.

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