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    Compound Interest Calculator

    See how your investments grow over time with compound interest. Enter a starting amount, monthly contributions, an expected return, and a time horizon to project your balance — and adjust for inflation to see it in today's money. No signup required.

    19.3K

    After 10 years · 49% total return

    Investment Growth

    How your money compounds year by year

    Total Value
    Total Invested
    Total Value
    Total Invested

    Your breakdown

    Key numbers behind the projection

    Final value

    19.3K

    Total invested

    13K

    Total gain

    6.3K

    Return multiple

    1.5x

    19.3K

    After 10 years · 49% total return

    Investment Growth

    How your money compounds year by year

    Total Value
    Total Invested
    Total Value
    Total Invested

    Your breakdown

    Key numbers behind the projection

    Final value

    19.3K

    Total invested

    13K

    Total gain

    6.3K

    Return multiple

    1.5x

    What it is

    This calculator shows how an investment grows over time with compound interest — the effect of earning returns on both your original money and the returns it has already generated.

    Enter your starting amount, a monthly contribution, an expected annual return, and a time horizon to see your projected balance, how much of it is contributions versus growth, and — if you turn on the inflation toggle — what the result is worth in today's money.

    How the math works

    Compounding
    Each month the balance is multiplied by (1 + annual rate ÷ 12), so growth earns further growth over time.
    Contributions
    Your monthly contribution is added every month after interest, steadily increasing the base that compounds.
    Real vs nominal
    The real line discounts the nominal total by inflation, showing what the balance buys in today's money.
    Return multiple
    Final value ÷ total invested — how many times your contributions have multiplied by the end.

    Assumptions & caveats

    • Returns are assumed steady; real markets are volatile and never grow at a fixed rate.
    • Interest is compounded monthly and contributions are added at the end of each month.
    • Taxes, fees, and changes to your contribution amount are not modelled.

    Frequently asked questions

    It's interest earned on both your original principal and the interest already accumulated. Because each period's gains are added to the balance, the next period earns on a larger amount, which compounds your growth over time.

    More frequent compounding produces slightly higher returns because interest starts earning interest sooner. This calculator compounds monthly, which is a common assumption for investment accounts.

    There's no single answer — it depends on your income, goals, and timeline. The calculator lets you test different monthly contributions to see how even small, consistent amounts add up over many years.

    Yes. Inflation erodes purchasing power, so a large future balance buys less than the same amount today. Turn on the inflation toggle to see your projected value expressed in today's money.

    Forecast your real portfolio growth

    Connect your accounts and selfinance projects your investment growth from your actual balances and contributions.

    Get started

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