Countdown to due date with colours green, amber and red to due date

[SharonC2013]

Hi,

I need to update one of my spreadsheets, so it colour codes to the due date.  Example over the course of a month week 4 to due date of vehicle service is colour coded green, 3 weeks to due date automatically changes to amber, and 2 weeks to due date changes to red.  Can anyone help me navigate this option please?

[#2]

@SharonC2013 

Conditional formatting might be what you are looking for.

=AND(B2-A2<=28,B2-A2>=21)

This is the rule for week 4.

=$B$2:$B$24

This is the range the formatting applies to in the example.