It looks like you would want to use OR instead of AND.

=IF(OR(ISBLANK($A1),(ISBLANK(B1))),"",$A1+1)

However, as I recall from reading other posts re charting, I believe you
would want to return #n/a instead of null, so try changing "" in the formula
to na()

=IF(OR(ISBLANK($A1),(ISBLANK(B1))),NA(),$A1+1)

Also, if the blanks are results of formulas, try changing isblank(a1) to a1=
""

=IF(OR($A1 = "",B1 = ""),NA(),$A1+1)
--
Kevin Vaughn


"slinger" wrote:

I'm trying to do a chart using dates. I would like to set it so that if A1,
or B1 is blank, then C1 is also blank. If BOTH A1 and B1 contain information,
then C1 = A1 + 1.

I have tried this, and it doesn't work.

=IF(AND(ISBLANK($A1)),(ISBLANK(B1))),"",($A1)+1

I have also tried a few other things, all of which don't work.

Any help would be greatly appreciated.