A family of Microsoft spreadsheet software with tools for analyzing, charting, and communicating data.
- Select the range starting with N1
- Home tab > Conditional Formatting > New Rule > Use a formula to determine which cells to format and put following formula and select Red Fill Colour
=AND(N1-TODAY()<=15,N1<>"")
- Put following formula for Yellow Fill Colour
=AND(TODAY()>=EDATE(N1,-3),N1-TODAY()>15)