Hi,

Spent most of the day sifting old forum threads for an answer to this question with no luck, so I thought it was about time I posted my own..

I am in search of a formula that will give me to total cost over time (X nr of months) for a subscription, currently costing me Y, which increases each month by an given percentage (Z %).
I have several of these, but to take one example:

I have a subscription which will cost me 115 usd for July. I expect this subscription to increase each month by approximately 15% (compared with the previous month).
So I'll expect a bill for 132 usd (115*1,15) in August, 152 (132*1,15) for September etc..

What I need is a formula which will add these monthly costs up for me, so that I can get the total cost for 2nd half of 2012, for 2013 etc..

Really appreciate your help with this
Ollie