How credit card interest works — and how to avoid paying it
Credit card interest rates in Canada typically sit between 19.99% and 25.99% — among the most expensive debt you can carry. Yet many cardholders never pay a cent of interest. Understanding the mechanics is the first step to joining them.
How interest is calculated
Card interest is charged as an annual percentage rate (APR) applied to your average daily balance. If you owe $1,000 for a full month at 20% APR, you accumulate roughly $16 to $17 in interest that month. Carried balances compound against you daily.
The grace period is your best friend
Most cards give you a grace period of about 21 days after your statement date. If you pay your statement balance in full by the due date, no interest is charged on new purchases at all.
The catch: the grace period usually only applies if you paid your previous balance in full too. Carry a balance once, and new purchases often start accruing interest immediately.
When interest charges surprise people
- Cash advances — these have no grace period and often a higher rate. Interest starts the day you withdraw.
- Balance transfers after the promo ends — remaining balances snap to the full purchase rate.
- Partial payments — paying $95 of a $100 bill means interest on the whole balance on some cards.
Four habits that keep interest at zero
- Set up automatic payments for at least the full statement balance
- Keep a buffer in your chequing account so autopay never bounces
- Use cash advances only in genuine emergencies
- If you must carry a balance, move it to a low-interest or balance-transfer card
Tip: If you regularly carry a balance, a low-interest card around 12% to 14% can save you hundreds of dollars a year compared with a rewards card at 20%+.
The bottom line
Credit card interest is entirely avoidable: pay the statement balance in full every month and use the grace period as free short-term credit. If debt has already built up, prioritize a paydown plan or a cheaper card before the compounding works against you.
This article is for informational purposes only and does not constitute financial advice. Rates and product details change frequently — always compare current offers before making a decision.
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