The difference between compound and simple interest on the same debt can stretch into thousands of dollars over a typical payoff window. Simple interest charges you only against the remaining principal each period. Compound interest charges you against the principal plus the interest already accumulated. On Canadian credit cards, that compounding runs daily, which is why a balance that looks small at 22% APR can take 8 to 10 years to clear on minimum payments, and end up costing more in interest than the original amount borrowed.
May 22, 2026. Figures in this article use standard amortization math on modeled $10,000 debt profiles. Rate disclosures follow the Cost of Borrowing Regulations under the federal Bank Act.
How Simple Interest Calculates Your Cost
Simple interest charges only your principal, never your accumulated interest. A loan at 12% simple interest on $10,000 owed for one year produces exactly $1,200 in interest. Two years produces $2,400. The math is linear. Most Canadian personal loans, auto loans, and unpaid Canada Revenue Agency balances use simple interest, billed monthly against your remaining principal.
Simple interest is the structure most Canadians learn first because it appears in everyday products. The Canada Student Loans Program switched its outstanding balances to a zero-interest model on the federal portion in 2023, while still using simple interest for provincial top-ups. Auto loans from the major banks and credit unions, personal loans, and most home equity lines of credit during their repayment phase calculate interest the same way: nominal annual rate, applied once per month, against whatever principal is still outstanding.
The structure has one consequence borrowers can rely on. As long as you cover at least the interest charge each month, the principal balance cannot accidentally grow. Your final payment is exactly the size your amortization schedule predicted on day one. There are no compounding surprises if you stay on schedule.
How Compound Interest Works on Canadian Credit Cards
Canadian credit cards apply a Daily Periodic Rate against your average daily balance, then add yesterday's interest into today's balance before the next day's calculation runs. At 22.99% APR, the daily rate is 0.063%. On a $10,000 balance that compounds to an effective annual rate near 25.83% by year-end, well above the printed APR.
Credit card interest in Canada is bound by the disclosure rules in the federal Cost of Borrowing Regulations, which require the nominal APR be shown on every statement. What is calculated against you is the Daily Periodic Rate, which the issuer derives by dividing the APR by 365. That fraction is multiplied against your average daily balance every single day of the billing cycle.
What turns this arithmetic into a pricing trap is the rollover. Each day's interest is added to the balance that gets multiplied the next day. The 365 compounding periods per year is the reason a 19.99% nominal rate actually costs closer to 22.13% per year if you carry a balance through every cycle. The grace period only helps if you pay the full statement balance by the due date. Carry anything forward and the daily clock starts the moment the new cycle opens.
The $10,000 Test: 5-Year Cost on Same Balance, Same Payment
Take $10,000 of debt held for five years against a $250 monthly payment. At 19.99% simple interest, total interest works out to roughly $4,164. At 19.99% compounded daily, that figure climbs to about $5,762. The structure of compounding, not the rate itself, adds nearly $1,600 in cost and 8 extra months of payments.
The math is easiest to see on a fixed example. Run the scenario twice: once as simple monthly interest at 19.99%, and once as compound daily interest at the same nominal rate. The compound version costs more, takes longer to clear, and pays down principal more slowly in every single year of the payoff. Year one alone shows a $172 gap. By year three the gap has grown past $870.
| Interest method | Total interest | Months to clear | Total paid |
|---|---|---|---|
| Simple 19.99% | $4,164 | 57 | $14,164 |
| Compound daily 19.99% | $5,762 | 65 | $15,762 |
The gap widens further at higher rates. At 24.99% on the same $10,000 with the same payment, the simple-interest run costs about $5,491 in total interest. The compound run costs about $7,956. Roughly $2,465 of additional cost shows up purely from the calculation method, not from any change in what was borrowed or how much was paid each month.
Which Canadian Debts Use Which Method
In Canada, credit cards, store cards, payday loans, and most revolving lines of credit use daily compounding. Personal loans, auto loans, and student loans through the Canada Student Loans Program mostly use simple monthly interest. The Financial Consumer Agency of Canada publishes the disclosure rules each lender must follow under the federal Bank Act.
The split runs along the lines of secured versus unsecured and revolving versus installment. Credit cards from Visa, Mastercard, and American Express, regardless of issuer, use daily compounding. Store cards from Canadian Tire, Walmart Rewards, and most retail chains do the same, often at rates above 28%. Payday loans calculate by the same daily structure at far higher rates, capped by provincial law in Ontario at $14 per $100 borrowed.
Installment debt mostly does not compound. Royal Bank of Canada, TD Canada Trust, Scotiabank, BMO, and CIBC offer personal loans, secured lines for cars and recreational vehicles, and unsecured term loans that bill simple monthly interest. Mortgages compound semi-annually under Section 6 of the Interest Act, which is mathematically much closer to simple interest than to daily compounding. A 30-year mortgage at 5% interest behaves very differently from a credit card at 19.99%, and the compounding structure is a large part of why.
If you are choosing where to put extra payments, the compounding debt costs more per dollar of balance than the simple-interest debt at the same nominal rate. That makes credit card balances the highest-impact target for any extra dollar, before personal loans, auto loans, or mortgages, even when their printed APRs look comparable.
Frequently Asked Questions
Canadian credit cards compound daily, applied against your average daily balance. At 22% APR, your daily periodic rate is 0.060% (22 divided by 365). On an $8,000 balance, that runs about $4.82 in interest per day, or roughly $146 in the first 30 days if no payment lands. Each day's interest gets added to the balance before the next day's calculation runs, which is why a $200 minimum payment can take 8 to 10 years to clear a balance of that size.
For consumer debt, the consensus is unambiguous. The Financial Consumer Agency of Canada, Equifax Canada, and Licensed Insolvency Trustees uniformly describe credit card compounding as the costlier structure compared to simple interest on personal loans or installment products. The disagreement among advisors is not whether compounding costs more. It is whether the spread is large enough to justify a consolidation move. A 22% credit card moved into a 12% simple-interest personal loan typically cuts interest costs in half over the same payoff window.
A credit card calculates interest daily on your average daily balance, then folds yesterday's interest into today's balance before the next calculation. A personal loan from Royal Bank of Canada, TD Canada Trust, or Scotiabank typically charges simple interest monthly against your declining principal, with each payment split between principal and interest on a fixed amortization schedule. Same nominal rate, different cost. A $10,000 balance at 12% APR runs about $1,200 in interest the first year on a personal loan and about $1,268 on a credit card.
No. The statement shows the dollar charge for the current month, but the calculation method determines how that charge grows over the next 30 days. Simple interest on a personal loan stops growing the second you make your payment. Compound interest on a credit card keeps growing on the unpaid portion every single day, including the interest that has already accumulated. Two debts of identical balance and identical rate can produce wildly different total costs by the time they are cleared.
At a 22.99% APR and a typical 2% minimum payment (about $100 on $5,000), the balance does not literally double. The total amount you pay does. Estimated payoff stretches to roughly 25 years with total payments near $11,400, more than double the original $5,000. The reason is that the minimum payment scales down as the balance drops, so each smaller payment covers a smaller share of principal while the daily compounding keeps applying to whatever is left.
Worst case modeled at 24.99% over a 7-year window with minimum-only payments, compound interest on a credit card costs roughly $13,200 more in total interest than simple interest at the same nominal rate on a 7-year personal loan. That gap widens with rate, balance, and payoff time. Licensed Insolvency Trustees consistently flag compounding credit card balances as the first debt to address in any Consumer Proposal review under the Bankruptcy and Insolvency Act.
About the Methodology
All figures in this article use standard amortization math on the inputs described. Daily periodic rate calculations follow the disclosure pattern required by the Financial Consumer Agency of Canada under the federal Cost of Borrowing Regulations. Modeled profiles assume fixed APR, consistent payments, and no new charges added to the balance during the payoff window. Real-world results vary based on grace period rules, billing cycle timing, missed payments, fee assessments, and changes to the statement balance. For personalized debt guidance, consult a Licensed Insolvency Trustee regulated by the Office of the Superintendent of Bankruptcy under the Bankruptcy and Insolvency Act.
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Compound Interest CalculatorUnburden is a planning tool. The Burden Score is an educational estimate, not financial advice. Consult a Licensed Insolvency Trustee for personalized debt guidance.