Calculate unit sales with recurring billing AND growth rate.

[Art]

Hi folks,

I'm building a worksheet to forecast unit sales. Our business does
recurring billing monthly (on a subscription), so I need to be able to
plug in a growth rate and have each month show a sum that includes in
the growth while also adding in all existing subscriptions. In other
words, I want to be able to show, say, a 2% growth rate each month for
new subscriptions, while still adding in existing ones into the total.

So, for instance, if I had a 10% monthly growth rate, and I started in
month 1 with 25 subscriptions, my monthly totals would look like:

1 2 3 4 5 6 <-- Month
-------------------------------
25 53 83 116 153 193 <-- Subscription sales (rounded)

I can do this using two cells for each month (one to calculate growth,
the other to add all the months, including the current month,
together), but I'd like to find a formula that will allow me to
calculate and show each month's total in a single cell.

I'm sure there's a nice easy formula/function, and I'm just missing
it.

Thanks!

Art

 

[Paul Lautman]

Well I tried =CEILING($A2*(1+A1/10)+A2,1) and that led to:

25 53 83 116 151 191