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INTERACTIVE TOOL

Compound Interest Calculator

Compounding is the quiet engine behind long-run wealth: each period's gains go on to earn gains of their own, so the earlier and longer you invest, the more time does the heavy lifting. This calculator projects how a starting balance plus regular contributions grow at a chosen rate, and charts the split between what you put in and what the market adds. Change the inputs to see why time in the market tends to matter more than timing it.

Final value
$300,851
Total contributions (incl. initial investment)
$130,000
Total interest earned
$170,851
$0$100K$200K$300K$400KNow5y10y15y20y
Balance Contributions
Formula used

A = P(1 + r/n)nt + PMT × [((1 + r/n)nt − 1) ÷ (r/n)]

P = initial, PMT = contribution per period, r = annual return, n = periods per year, t = years.

Free and private: the numbers you enter stay in your browser. Educational only, not investment advice.

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