Compound Interest Calculator
Model A = P(1 + r/n)nt, continuous compounding, or add monthly contributions. Compare the effective annual rate (EAR) when compounding frequency changes.
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Final amount
Year-by-year balance
| Year | Balance | Interest so far |
|---|
Ideas behind compounding
Albert Einstein is often quoted as calling compound interest โthe eighth wonder of the worldโ โ the quote is widely attributed but not well verified. The underlying idea is sound: when interest earns interest, growth accelerates over long horizons.
Rule of 72: roughly 72 รท annual percent rate estimates years to double money at constant compounded growth (handy, not exact).
EAR: The effective annual rate lets you compare nominal rates that compound at different frequencies โ more frequent compounding within the year lifts the effective yield slightly.
This page is currency-agnostic โ pick a display currency; math is the same. Fees, tax, and inflation are not modeled.
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