Use the IFERROR function to trap and handle errors produced by other formulas or functions. IFERROR checks for the following errors: #N/A, #VALUE!, #REF!, #DIV/0!, #NUM!, #NAME?, or #NULL!.
For example, if A1 contains 10, B1 is blank, and C1 contains the formula =A1/B1, the following formula will trap the #DIV/0! error that results from dividing A1 by B1:
=IFERROR (A1/B1. "Please enter a value in B1")
In this case, C1 will display the message "Please enter a value in B1" if B1 is blank or zero.