The #DIV/0! error value occurs when a formula divides by 0 (zero).
Cause
Using the cell reference to a blank cell or to a cell that contains zero as a divisor. (If an operand is a cell that is blank, Microsoft Excel interprets the blank as zero.)
Cure
Change the cell reference, or enter a value other than zero in the cell used as a divisor. You can enter the value #N/A into the cell referenced as the divisor, which will change the result of the formula to #N/A from #DIV/0! to denote that the divisor value is not available.
To prevent an error value from displaying, use the IF worksheet function. If the cell used as the divisor is blank or contains a zero (0), then the IF function can display nothing instead of performing the calculation. For example, if cell B5 contains the divisor and A5 contains the dividend, use =IF(B5=0,"",A5/B5). The two quotation marks represent an empty text string.