Put the following forumula in a cell adjacent to the dates on your calendar:
=Mod("date"/6,1). It will yield 6 results, .333...,.5,.666...,.833...,
0,.166..., where "date" is the numeric value for that given date. Use
conditional formatting to mark the date. For the date that results in
..333... set the conditional formatting to Formula Is with the formula
"=A8=(1/3)" (set to the address for your formula) and set to conditional
formatting to whatever you like. Do the same for .5 and .666... and you'll
have a pattern that highlights every block of three days. You'll need to
adjust the conditional formatting to whichever days you have on or off.
Gary

"wrg415b" wrote:

I work 3 days on and 3 days off . How can I make a calender reflecting this
using 2 colors without physically editing each day?