I’ve always been pants at mathematics. If I have a series of small but incrementally applied percentage increases (say 18% applied 7 times), is there a simple way of calculating the overall increase to the original sum as a single percentage value?

1.18^7?

Yes.

Hope that helps.

f = x * p^n

f = final value
x = initial value
p = percentage as a multiplier = (percentage / 100) + 1
n = number of times
^ = ‘to the power of’

I think that’s right…

Assume it is compound interest.
Formula for compound interest is
A=P(1+r)^n
Where A is final amount, P is principle (starting amount), r is rate for the time period (as a proportion, not percentage) and n is the number of time periods.

Yes.

You already spotted that the answer isn’t 1.18 x 7

It’s 1.18 to the power of 7

1.18 x 1.18 is 1.18 to the power of 2 (1.18^2)
1.18 x 1.18 x 1.18 is 1.18 to the power of 3 (1.18^3)
1.18 x 1.18 x 1.18 x 1.18 is 1.18 to the power of 4 (1.18^4)
etc

Desktop calculators won’t do it, but excel and scientific ones will, as will the google search bar.

Anyone else like to rewrite the same answer in a slightly different way?

Multiply by 3.18547390057.