Formula? Do calculation or give error message if wrong data entered?

[tbarrows112]

Hello,

I have a (hopefully) somewhat simple question however I am struggling to know how to write the formula for this in Excel as I can only really do the basics.

Essentially, I have an 'X' cell, and a 'Y' cell. In cell 'Z' I want it to calculate the percentage difference of X to Y. Both cells X and Y will be updated by the user and presented with the answer in cell Z. However, if the user enters anything other than a number in cell 'X' I'd like the Z cell to say "please check cell x", and the same rule applying to cell y but saying "please check cell y".

Is this possible? And can anybody please advise me how to do this by helping with me with the formula I have to input?

Thank you in advance!!

Best Regards,

 

[jtakw]

Hi,

What if both X and Y are not numbers, scenario included in formula:

Excel 2010
	X	Y	Z	AA
1			Column formatted as Percentage
2	10	100	10.00%	10.00%
3	this	100	Please check Cell X	Please check Cell X
4	10	that	Please check Cell Y	Please check Cell Y
5	this	that	Please check Cells X and Y	Please check Cells X and Y
Sheet3

Cell Formulas
Range	Formula
Z2	=IF(COUNT(X2:Y2)=0,"Please check Cells X and Y",IF(NOT(ISNUMBER(X2)),"Please check Cell X",IF(NOT(ISNUMBER(Y2)),"Please check Cell Y",X2/Y2)))
AA2	=IF(COUNT(X2:Y2)=2,X2/Y2,"Please check "&IF(COUNT(X2:Y2)=0,"Cells X and Y",IF(NOT(ISNUMBER(X2)),"Cell X","Cell Y")))

Edit: Shorter formula in AA2