The only way that your formula could return 30-Jan-00 is if A1 contains a
number =0, <1 or the logical value FALSE.

If A1 is empty or contains a formula blank ("") the result will be "".

Maybe A1 contains 0 but you have 0 display turned off: ToolsOptionsView
tabZero display.

Try this (assuming that only true Excel dates are to be entered in A1):

=IF(AND(COUNT(A1),A10),A1+30,"")


--
Biff
Microsoft Excel MVP


"Eileen" wrote in message
...
I am trying to enter a formula to calculate a date 30 days later in cell b1
only if cell a1 has a date. If cell a1 does not have a date then leave b1
blank. I am getting a return date of 30-Jan-00 when cell a1 is blank. I
don't
understand why 30-Jan-00 comes up. This is the formula that I am using:

=IF(ISBLANK(A1),"",IF(COUNT(A1+30),A1+30,""))

Thank you in advance for your help.
Eileen