Conditional Formatting in Excel
Conditional formatting changes a cell's appearance — fill color, font, icon — automatically when its value meets a rule you set. Instead of manually coloring cells, you write one rule ("greater than 100", "contains text", "is blank") and Excel applies it to every cell in the range, and keeps it updated as the data changes.
Worked example
Highlight Cell Rules → Greater Than → 100Every cell over 100 in the selected range turns the chosen color
Excel also supports a formula-based rule (Use a formula to determine which cells to format) for anything the built-in presets can't express.
The rule types you'll actually use
Highlight Cell Rules covers the basics: greater than, less than, between, equal to, text that contains a value, dates in a range, and duplicate values.
Top/Bottom Rules flags the highest or lowest N values, or the top/bottom percentage — useful for surfacing outliers in a sales or scores column without sorting.
Data Bars, Color Scales, and Icon Sets turn a column into a mini visualization in place — a color scale is a fast way to spot where a whole table is trending high or low.
Common mistake: applied range vs. selected range
A rule only applies to the cells you had selected when you created it. If you add new rows below your original range, they won't be formatted until you edit the rule's applied range (Conditional Formatting → Manage Rules) to include them.
Practice this for real
Try the "Conditional Formatting" exercises
Type the formula into a real spreadsheet and get instant feedback.