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Compound interest calculator

Future value of savings with monthly contributions, compounding and inflation. Educational, not financial advice.

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Educational, not financial advice. Assumes a constant rate; real investment returns vary and can be negative.

How it works

Compound interest means you earn returns on your returns, so growth speeds up over time. This answers: "If I start with $X, add $Y a month and earn Z% a year, what will I have?" Works for savings, index funds or crypto yield.

  1. 1
    Starting pointPrincipal and monthly contribution
  2. 2
    Rate & timeAnnual rate, compounding, years
  3. 3
    See the growthFuture value, interest, real value

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Disclosure: some links are affiliate or sponsored links (labelled); we may earn a commission at no extra cost to you. Placement in this list is editorial except items marked Sponsored. Educational, not financial advice.

Questions, answered

What is compound interest?

Earning interest on both your original money and on interest already earned. Over long periods this makes balances grow faster and faster.

What does compounding frequency change?

How often interest is added. More frequent compounding (daily vs annually) gives a slightly higher effective yearly rate for the same stated rate.

What is real value?

Your future balance expressed in today's dollars, after dividing out the inflation rate you enter. It shows purchasing power.

Can I use this for stocks or crypto?

Yes as a what-if, but stock and crypto returns are not fixed: they vary year to year and can be negative. Treat the rate as an assumption, not a promise.

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