Compound Interest Calculator

Project your savings — future value, interest earned and a year-by-year breakdown, with a goal-seek mode.

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$
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More options — inflation, raises & timing
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$244,000
Future value

    Balance over time

    Year-by-year breakdown

    Estimates only — real investment returns vary and are not guaranteed. The $ is just a label; the maths works in any currency.

    How to use the compound interest calculator

    In Grow mode, enter your initial deposit, a regular contribution and how often you add it, your expected annual interest rate, how often it compounds, and how many years you'll invest. The future value, the split between your contributions and the interest they earn, a growth chart and a year-by-year table update instantly. Open More options to add an inflation rate (for the value in today's money), model annual raises to your contribution, or switch the timing. Switch to Goal mode to work backwards from a target.

    How does compound interest work?

    Interest is added to your balance, and future interest is earned on that larger balance too — so growth accelerates the longer you stay invested. For a lump sum the future value is A = P·(1 + r/n)n·t, where r is the annual rate, n the times it compounds per year, and t the years.

    How does compounding frequency affect returns?

    More frequent compounding (daily vs. annually) earns a little more because interest is added sooner and starts earning itself. The gap widens with higher rates and longer horizons, but it's usually small next to the rate and your contributions.

    How do regular contributions change the result?

    Every contribution starts earning interest from the moment it's added, so steady deposits often add far more to the final balance than the initial lump sum — especially over long periods. The chart shows your contributions and the interest they earn as two stacked bands.

    What is the inflation-adjusted (real) value?

    It restates the future balance in today's money by discounting for inflation, so you can see what it would actually be worth. Enter an inflation rate under More options and the “in today's money” figure appears.

    How does the savings goal calculator work?

    In Goal mode, enter a target amount and the calculator solves for either the regular contribution or the time needed to reach it — given your starting deposit, interest rate and compounding frequency.

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