How Credit Card Interest Works in Canada (and How to Pay $0)

Here's the most important thing to know about credit card interest: if you pay your statement balance in full every month, you pay no interest at all — regardless of your card's rate. That's thanks to the grace period. Master that one habit and the rest is detail.

The grace period

When your statement closes, you have a grace period (usually 21 days) before the balance is due. Pay the full statement balance within that window and the issuer charges you nothing for borrowing the money. This is why a card's interest rate is irrelevant to anyone who pays in full — and why rewards cards make sense for them.

How interest is calculated when you carry a balance

If you don't pay in full, two things happen:

1. You're charged interest on the unpaid balance, typically at around 20% APR.
2. You usually lose the grace period on new purchases until you're paid off — so interest starts accruing on new spending immediately.

Interest is generally calculated daily: your annual rate divided by 365, applied to your average daily balance. At ~20% APR, a $1,000 balance costs you roughly $16–17 a month until it's cleared.

How to pay zero interest

• Always pay the full statement balance, not just the minimum.
• Automate it — set up an automatic full-balance payment so you never slip.
• If you already carry a balance, focus on paying it down before chasing rewards. A low-interest or balance-transfer card can help you get there faster.

Rewards only make sense once you're paying in full. If that's you, see which card pays you the most with our rewards calculator, or compare all cards to find your match.