Your estimated compound interest result
The final balance is the starting amount grown at the rate you entered, plus any monthly contributions grown the same way. Total interest is what is left after subtracting everything you put in.
Free tool · Canada · Estimate only
Compound Interest Calculator
Enter a starting amount, an annual interest rate, a number of years and how often interest compounds to see the final balance, what you put in and how much of the balance is interest. Add an optional monthly contribution if you plan to keep adding money. This is an estimate only — plain arithmetic on the numbers you enter. It is not advice.
Written November 14, 2026
The amount you start with, before any interest or added contributions.
The yearly rate you want to test, as a percentage — for example, enter 5 for 5% a year.
How long the money stays in, in whole years.
Enter 1 for yearly, 2 for twice a year, 4 for quarterly, 12 for monthly or 365 for daily compounding.
An amount you add every month, on top of the starting amount. Leave at 0 if you are not adding anything.
How the estimate works
The formula. Final balance of the starting amount = P × (1 + r ÷ n)n × t, where P is the starting amount, r is the annual rate as a decimal, n is the number of compounding periods per year and t is the number of years. A monthly contribution is grown month by month at the monthly rate that matches the compounding you entered: monthly rate = (1 + r ÷ n)n ÷ 12 − 1, and the contributions total c × ((1 + monthly rate)12 × t − 1) ÷ monthly rate, where c is the monthly contribution. At a 0% rate, the final balance is simply the starting amount plus all the monthly contributions. Total contributions = starting amount + monthly contribution × 12 × years. Total interest earned = final balance − total contributions.
Assumptions printed. The result uses exactly the numbers you entered, with the rate held steady, contributions added at the end of each month, and no tax, fees or inflation.
Sources: No external figure is used on this page. Every number in the result comes from the numbers you enter and the formula above.
Next step: read the full step-by-step guide: How to Open a TFSA in Canada