Use Format | Conditonal Formatting with a formula of:

=A1B1+3*365

assuming that the cell you want to change is A1.

Hope this helps.

Pete

On Jul 18, 7:01*pm, "Tony" wrote:
ok thanks for my last post
what if i want to put a date in colum 1 and when its the value in column 2
past ie 36 months past that date i want the date cell to turn red
Thanks Tony