September 16, 200619 yr Hello everyone, I'm trying to model a savings account. Two tables, Accounts and their related transactions. The sum of the transaction amounts give the account balance. Simple enough.. But how to calculate a compounded interest? My thought was to add an interest transaction each time something changed either the interest rate or the addition of a transaction. But I can't find a formula for calculating compunded interest. I have Interest rate The startting balance The amount of time All the functions I see have you putting in payments. This is just one lump sum over time. Many thanks in advance! -jim lee
September 16, 200619 yr There are two ways to compound interest: periodically and continuously. The future value of a deposit with periodically compounded interest is: principal * ( 1 + rate )^nper where rate is the interest rate PER COMPOUNDING PERIOD, and nper is the number of compounding periods. The future value of a deposit with continuously compounded interest is: principal * Exp ( rate * nper ) where rate is the interest rate per any arbitrary period, and nper is the number of those periods.
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