Question: how to create a formula in excel to change color based on date?
Answer: Select cell A1.
Choose Conditional Formatting from the Format menu. ... 
Set Condition 1 so that Cell Value Is Equal To =TODAY(). ... 
Click on the Format button. ... 
Make sure the Patterns tab is selected. ... 
Choose the red color you want to use and close the Format Cells dialog box.
Click on the Add button.