Basic Functions: COUNTBLANK
The COUNTBLANK function allows you to total the number of blank or empty cells in a specified range.
It is used as show n below in the example. Cells C3, B5 and D5 are empty - so the COUNTBLANK function in D7 returns 3.
You may have a situation where the array is quite large and it is important that each cell has a value. To make it easier to trap blank cells, you can combine the COUNTBLANK inside an IF function…
=if(COUNTBLANK(A1:A500)>0,”Blank Cell”,average(A1:A500))
Conditional formatting would also help you spot blank cells.