Compounding Opex formula

Hi Forum,

I am not sure if this is the right place for my query, but i am struggling with a (what i think is )a simple way of representing a formula.

So here is what it is.

I have an initial cost value , let's say 100 for year 1.
I want this value to increase at a rate of 5% each year.
I want to know my total cost at year n.

So if we take an example for 3 years.
r= my rate (i.e. 5%(0.05))

=100+100*(1+r)+((100*(1+r))*(1+r))

I am creating a userform which will populate the number of years and the rate in two cells. I just need the formula in my third cell to give me the total value.

Can anyone help here ?

Kind regards,

xvx_warrior

If your cost is increasing by 5% year-on-year then all you need is a compound interest formula.

So if, say, your value is in A1, and the number of years is in A2 then your formula would be:

=A1*(1.05)^A2

Hi, thanks for your reply. However this is not what i am looking for. The compounding interest formula gives me my interest at the end of "n" years. What i actually want is :
interest = 5%
years = 3

i have my cost for year 1 = 100
my cost after interest at year 2 is = 105
my cost after interest at year 3 is = 110.25

My total cost is 100+105+110.25 = 315.25

not only how much interest i will have at the end of "n" years.

Any other ideas ? :/

I'm sure that there's a mathematically neater way, but why worry about that when we can use plain old brute force

=SUMPRODUCT(A1*(1.05)^(ROW(INDIRECT("1:" & A2))-1))

Yeah, pretty sure there should be. But Brute force it is. Works perfectly well. Thanks Andrew-R. I'll mark it as solved.