Annual Compound Interest Formula

P = Principle Investment.
r = Interest Rate.
R = ( 1 + r) .
Sumn = Sum at the end of the nth Term.
n = Number of periods (Yrs,Mths, Days).

NB:- If period = days and interest rate is Annual then :-
n = number of days /365

Invest Sum "P" compounded at interest rate (1+ r) = "R" for "n" yrs.
Sumn = P(1 + r) ^n or Pr ^n

Example:- Invest £4000 for 500 days @ annual interest of 10% = 0.1

Sumn = 4000*(1+0.1)^(500/365) = £4557.87

Use this formula in your Spreadsheet

Regards Mick