How compound frequency calculator works
Compound interest grows faster when interest is credited more often, because each new interest payment itself starts earning interest sooner. This calculator compares nine compounding frequencies — annual, semiannual, quarterly, monthly, semimonthly, biweekly, weekly, daily, and continuous — side by side for the same principal, annual rate, and term, so you can see exactly how much the frequency alone is worth.
For each frequency the calculator uses the standard formula A = P(1 + r/n)^(nt), where r is the annual rate as a decimal, n is the number of compounding periods per year, and t is the years. The effective annual rate (APY) for each frequency is (1 + r/n)^n − 1, and for continuous compounding the formula becomes A = Pe^(rt) with an APY of e^r − 1. An optional monthly contribution is added as an annuity so you can compare contribution scenarios too.
The biggest jump comes from moving annual to monthly compounding; beyond monthly the gains shrink fast because the periods are already so short. The tool highlights the best and worst final balances and the spread between them so the frequency effect is obvious at a glance. This is an estimate for education, not investment advice.