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Compound Interest Calculator

↻ Updated 2026

Enter a starting balance, monthly contribution, rate and compounding frequency to see how compound interest grows your money over the years.

Educational calculators — always consult a licensed professional before making financial decisions.

Your inputs

Starting principal

Monthly contribution

Annual interest rate

Years

Compounding frequency

Future balance

$264,122

after 20 years

You contributed

$130,000

$500/mo + start

Interest earned

$134,122

103% on contributions

Balance growth6% · 20 yr

todayyear 20

Where the money comes from

Contributions$130,000

Interest$134,122

ASSUMPTIONS — Interest compounds monthly; contributions are added monthly. Returns are assumed constant — real markets vary year to year. Figures are before taxes and inflation; sheltering the money in a TFSA or RRSP defers or eliminates tax on the growth.

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Sources & rate references

·Standard amortization / compound-interest formulas

Rates, brackets and limits here are checked against primary sources. If a number still looks off, email support@realmoneyiq.com and we'll review and fix it.

RealMoneyIQ provides free educational calculators, not financial, tax, investment or legal advice. Results are estimates based on the assumptions you enter and publicly published rates; your actual outcome will differ. Always confirm decisions with a licensed professional who knows your full situation.