Sometimes you want to wait to work out something on your spreadsheet until you have the input. This is where ISBLANK is a useful function.
The structure is simple: =ISBLANK(value) One input, which usually would be the reference to your input cell.
As is often the case, things are not always clear cut and there are some subtleties that are worth exploring.
B4 shows TRUE. This is because B2 has nothing in it.
C4 is FALSE. This is because C2 has 5 in it, therefore it is not blank.
D4 is also FALSE. This is because D2 has a formula in it, despite the fact the that formula is pointing to the blank cell B2!
So where might this actually be useful?
Instead of using the ISBLANK function by itself, it is best used in conjunction with the other functions, namely IF.
Let’s look at an example.
In row 4 we are using the ISBLANK function to only calculate the pay when a value has been entered for the number of hours. So B4 is asking for the hours to be entered because B2 is blank, whereas D4 shows zero (0 * 40) as the ISBLANK function “sees” that the input cell D2 is NOT blank, even though it is returning exactly what is in B2 which IS blank.
To find out more about the IF function look here.