Luke,
try typing
=IF(L2<"",COUNTBLANK($L$2:L2),"")
at Cell M2 and
=IF(L3<"",COUNTBLANK($L$2:L3)-SUM($M$2:M2),"")
at Cell M3.
Expand the formula of M3 at all remianing rows below it.

You can change the "" with "n.a.", 0 (zero) etc. if you don't want blank
cells.

Hoping that this is what you were looking for.


"Luke" wrote:

I need formula in column M to count number of blank cells in column L since
the last entry
Sheet looks like this:
L2 1 M2
L3 M3
L4 M4
L5 M5
L6 1 M6 3
L7 1 M7 0
L8 M8
L9 1 M9 1

Thank you
Luke