The Basics of Loan Interest
Interest is the fee a lender charges you for the privilege of borrowing money. It is expressed as a percentage of the loan's outstanding balance, and it is how lenders earn revenue on the funds they lend.
When you take out a personal loan, you agree to repay the principal (the amount borrowed) plus interest over a set period. The interest is calculated based on your loan's interest rate, the principal balance, and the length of the loan term.
Understanding how interest works helps you make better decisions about which loan to choose, how much to borrow, and whether to prioritize paying off your loan early.
Simple Interest vs. Compound Interest
Most personal loans use simple interest, which means interest is charged only on the outstanding principal balance. As you make monthly payments and reduce the principal, the amount of interest charged each month decreases.
Compound interest, by contrast, charges interest on both the principal and any accumulated unpaid interest. While compound interest is common for savings accounts and credit cards, it is relatively rare in personal loan products.
In Canada, the vast majority of personal loans from banks, credit unions, and online lenders use simple interest calculations. The Cost of Borrowing disclosure will specify the total interest cost over the life of the loan.
| Feature | Simple Interest | Compound Interest |
|---|---|---|
| Interest charged on | Principal only | Principal + accrued interest |
| Total cost | Lower (for same rate) | Higher (for same rate) |
| Common in | Personal loans | Credit cards, some lines of credit |
| Early repayment benefit | Significant savings | Moderate savings |
How Amortization Works
Personal loans use an amortization schedule that divides your total repayment into equal monthly installments. Each payment contains two components: a portion that goes toward interest and a portion that reduces your principal balance.
In the early months of your loan, a larger share of each payment goes toward interest because your outstanding balance is highest. As you pay down the principal, the interest portion decreases and more of each payment goes directly toward reducing what you owe.
This front-loading of interest costs means that making extra payments early in the loan term can significantly reduce your total interest expense, as it reduces the principal on which future interest is calculated.
Save on Interest
Even small extra payments toward principal in the first year of your loan can save you significant money in total interest. Check that your lender does not charge prepayment penalties before making extra payments.
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Calculating Your Total Cost of Borrowing
The total cost of borrowing includes all interest payments plus any fees charged by the lender. To calculate this, you need to know three things: the loan amount, the interest rate (APR), and the loan term.
For example, borrowing CAD $10,000 at 10% APR for 3 years results in approximately CAD $1,616 in total interest, bringing your total repayment to approximately CAD $11,616. The same loan at 15% APR would cost about CAD $2,479 in interest.
Use an online loan calculator to model different scenarios with varying rates and terms. This helps you understand how changes in rate or term length affect your total cost.
Factors That Increase Your Interest Cost
Several factors can increase the total interest you pay on a personal loan. Being aware of these factors allows you to make adjustments that minimize your costs.
- Longer loan terms: Spreading payments over more months means more interest accrues
- Higher interest rates: Even small rate increases compound over time
- Origination fees: These are often rolled into the loan, increasing the effective cost
- Payment-only minimums: Making only minimum payments means slower principal reduction
- Late payments: Missed payments may trigger penalty rates or fees
- A 5-year term at 10% APR costs nearly 70% more in interest than a 2-year term at the same rate
- Rolling fees into your loan principal increases the amount on which interest is calculated
Strategies to Minimize Interest
You have several options for reducing the total interest you pay on a personal loan.
- Choose the shortest term you can comfortably afford
- Make extra payments toward principal when possible
- Set up biweekly payments instead of monthly to make an extra payment each year
- Refinance to a lower rate if your credit improves after taking the loan
- Avoid adding fees to the loan principal
- Compare total cost of borrowing disclosures across Canadian lenders
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