microsoft excel - Sum contents in column from starting cell on down without setting an explicit last cell index

I have an Excel spreadsheet and would like to sum the numbers in a column starting at one cell (say, B5) and continuing down to the last number in that column.

I know I could just enter a large ending index, like:

SUM(B5:B99999)

But ideally I could just say something like:

SUM(B5:...)

And it would sum from B5 all the way down.

I saw this Superuser question - Excel: is it possible to sum an entire column without setting explicit cell boundaries? - which provides a solution for summing all of the numbers in a column via the following formula:

SUM(B:B)

Problem is, I don't want to sum all of the numbers, just those starting in B5 and down.

Thanks

Answer

For Excel 2003 or before:

=SUM(B5:INDEX(B5:B65536,MATCH(TRUE,INDEX(ISBLANK(B5:B65536),0,0),0)-1,0))

For Excel 2007 or after:

=SUM(B5:INDEX(B5:B1048576,MATCH(TRUE,INDEX(ISBLANK(B5:B1048576),0,0),0)-1,0))