Calculators / Compound Interest Calculator
Compound Interest Calculator
See how a starting amount and regular monthly contributions can grow over time when your returns are reinvested and compound month after month.
How compound interest works
Compound interest is interest earned on both your original contribution and on the interest you’ve already earned. The earlier you start and the longer your money stays invested, the more of your eventual balance comes from growth rather than your own contributions — which is why time matters more than almost any other factor in long-term investing.
Example
Starting with $5,000 and contributing $200 a month at a 6% average annual return, you’d have contributed $53,000 after 20 years — but your account would be worth roughly $96,000, meaning growth accounts for close to half of the total.
Frequently asked questions
Is a 6% return realistic?
Long-run average annual returns for a diversified stock portfolio have historically been in that range before inflation, but returns vary significantly year to year and are never guaranteed. Use a rate that matches your own investments and risk tolerance.
Does this account for taxes?
No — this is a pre-tax growth estimate. Investments held in a TFSA grow tax-free; in an RRSP, growth is tax-deferred until withdrawal; in a non-registered account, growth may be taxed annually depending on the type of income.
What’s the single biggest lever I can pull?
Time. Starting a few years earlier, even with smaller contributions, often outweighs contributing more later — because more of your money has had time to compound.
Explore TFSA and RRSP investing
See how registered accounts can shelter this growth from tax.