How it works
Compound interest formula: A = P(1 + r/n)^(nt) for the initial amount, plus the future value of regular contributions added at each period. P is principal, r is annual rate, n is compounding periods per year, t is years.
Example
10,000 initial, 200/month, at 6% compounded monthly over 15 years grows to roughly 82,700 — about 46,000 contributed plus roughly 36,700 in interest.
Assumptions & limitations
Assumes a constant interest rate and consistent contributions, which real investments rarely deliver exactly. Treat results as an estimate, not a guarantee — actual returns depend on market performance.
Frequently asked questions
Does this account for inflation?
No. Use the inflation calculator alongside this one to see real (inflation-adjusted) purchasing power.
What compounding frequency should I choose?
Match it to your account — savings accounts often compound daily or monthly; check your provider's terms.