On Feb 27, 1:20 pm, bobmount
wrote:
I'm trying to find a formula (ideally) in Excel that will allow me to take a
constant weekly sales growth rate (based on 2006 actuals), and apply it to
the current week's actual sales amount...resulting in a 2007 year-end sales
estimate.

Giving you want I think you asked for:

=sum(C1:C8) + fv(A1, 52 - 8, 0, -C8)

where C1:C8 are the actual weekly sales amounts for the first 8 weeks
of 2007, and A1 is the average weekly sales growth rate based on 2006
actuals.

That is certainly not the way that I would estimate year-end sales.
So perhaps I misunderstand you. If so, please clarify your question.