Hi,

Try this

=SUM(OFFSET(A1,COUNTA(A:A)-12,):OFFSET(A1,COUNTA(A:A),))

If there are less than 12 valuse in the range the formula will give an error.

Mike

"Michelle D" wrote:

I have a table of hours worked by temporary staff which I am constantly
adding new values to. I need to calculate average hours worked from the last
12 weeks they worked at any given moment so I want a total of there hours for
the last 12 weeks.

I have limited knowledge of excel - so at the moment - I add the latest
value - then recalculate the sum of those 12 cells - I would like a table
that automatically calculates the sum of the last 12 cells in a column -
whatever cells they are.

Hope you can help,

Michelle