Hi All

I am trying to apply data validation to an output cell (a cell containing a formula) rather than an input cell, as is normally the case. Excel (2007) allows me to apply a condition (decimal,between,0.1-60 [yrs]) but the only way I can get the error ‘highlighted’ is by selecting “circle invalid data” (which draws an oval shape around the cell in question). The user will be unaware of this (!), so how do I make the warning message pop up when one of the associated input cells causes the result to be out of range?

For example
A1: 01/02/1956 ….UK date format, dd/mm/yyyy
A2: 19/09/2011
A3: =(A2-A1)/365 .. to give the answer in years

Then I want to apply the above validation to A3. If answer (age) is not in range 0.1-60, display error message (warning type) when a date cell (either) is entered. Could test the date cells themselves, but that makes life more complicated.

For example, if date in A1 (which is date of birth) is entered as 01/02/1947, this should immediately produce the error message (ref: Error Alert tab within the Data Validation dialogue box). I’m sure I could do something with conditional formatting, but the indications are that it can be done using validation, as Excel knows that the result data (in A3) is invalid in the case..

Thanks a lot, Phil