Compound interest calculator
See how a starting amount and regular monthly contributions grow over time, and how much of the total comes from compounding rather than your deposits.
Free · No sign-up · Updated October 2026
$232,643after 20 years
- You put in
- $130,000
- Growth from compounding
- $102,643
- Growth share of the total
- 44%
Before tax and fees. In a TFSA, growth is tax-free; outside registered accounts, interest is generally taxable.
How it grows
| Year | Contributions | Growth | Balance |
|---|---|---|---|
| Year 5 | $40,000 | $6,837 | $46,837 |
| Year 10 | $70,000 | $24,111 | $94,111 |
| Year 15 | $100,000 | $54,782 | $154,782 |
| Year 20 | $130,000 | $102,643 | $232,643 |
How this calculator works
Monthly steps
We grow the balance each month at a rate that matches your chosen compounding, then add your contribution at the end of the month.
Yearly, monthly and daily compounding give slightly different results at the same stated rate, which you can compare with the toggle.
Before tax and fees
Results don’t include fees, taxes or inflation. Investment returns vary from year to year, so a steady rate is a simplification.
Savings account and GIC rates can change, so confirm the current rate with the institution.
Questions
What is compound interest?
It’s interest earned on your original money and on the interest it has already earned. Over long periods, that growth on growth can end up larger than what you put in.
How much will $10,000 grow in 20 years?
At 5% compounded monthly with no further deposits, $10,000 grows to about $27,126 in 20 years. Adding $500 a month brings it to about $232,643. Returns on investments aren’t guaranteed, so treat these as examples.
How often do Canadian savings accounts compound interest?
Many calculate interest daily and pay it monthly, but practices vary. Check the account’s terms; the calculator lets you compare yearly, monthly and daily compounding.
What is the rule of 72?
A quick estimate of how long money takes to double: divide 72 by the annual return. At 6%, that’s about 12 years, close to the exact figure.
Is compound interest taxed in Canada?
Interest earned outside registered accounts is generally taxable as income each year. Growth inside a TFSA is tax-free, and growth inside an RRSP is taxed when you withdraw. For your situation, check with the CRA or a tax professional.
Do GICs pay compound interest?
Some do. Compound GICs reinvest interest until maturity, while others pay interest out annually, semi-annually or monthly, which doesn’t compound. Check how a GIC pays before comparing rates.
Results are estimates for general information, not financial advice. Confirm rates, fees and terms with your card issuer or bank. See our methodology.