Hello Joe,

I suggest you make the months actual dates, so E1 would be 1st Jan
2009, F1 1st Feb 2009 etc (all 1st of the month) - you can format as
mmm-yy to show just month and year.

Same applies to column D, make D2 1st Mar-09 and similar for D3, D4 etc
and again format as mmm-yy

Now you can use this formula in E2 copied across and down

=IF(OR(E$1<$D2,E$1EDATE($D2,$C2-1)),"",$B2/$C2)

regards, barry


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barry houdini
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