Introduction
When you apply for a mortgage, car loan, or personal loan, you'll see two percentages: the interest rate and the APR (Annual Percentage Rate). Most people focus on the interest rate because it's usually the smaller number and sounds more favorable. But APR is the more important figure for comparison shopping — and understanding the difference can save you thousands of dollars over the life of a loan.
What Is the Interest Rate?
The interest rate is simply the cost of borrowing the principal, expressed as a percentage. If you borrow $200,000 at 6% interest, you'll owe 6% of the outstanding balance in interest each year. The interest rate does not include any additional fees charged by the lender — it's a narrow, incomplete picture of the true cost of borrowing.
What Is APR?
APR is a broader measure that includes the interest rate plus most fees and costs associated with the loan, expressed as a yearly rate. For mortgages, APR typically includes origination fees, discount points, mortgage broker fees, and certain closing costs. For credit cards, APR is essentially the same as the interest rate, since there are usually no additional fees rolled in. By law in the US, lenders must disclose APR under the Truth in Lending Act, giving borrowers a standardized way to compare loan offers.
How to Use APR for Comparison Shopping
When comparing two mortgage offers with different rates and fee structures, always compare APRs, not interest rates. A loan with a 6.0% interest rate and high origination fees might have an APR of 6.4%, while a loan at 6.2% with no fees might have an APR of 6.25%. The second loan is cheaper overall despite the higher stated rate. For short-term loans or if you plan to sell or refinance within a few years, the interest rate matters more — you won't have the loan long enough for fees to be fully amortized.
Credit Card APR
Credit card APR works differently. Most cards have a purchase APR, a balance transfer APR, and a cash advance APR — all potentially different. Credit cards in the US compound daily, which means the effective annual rate (EAR) is slightly higher than the stated APR. A 24% APR compounding daily has an effective rate of about 27.1%. Always pay your full balance to avoid any interest charges.
Conclusion
APR is the number to compare when shopping for loans. It standardizes total cost across different fee structures and makes true apples-to-apples comparison possible. Use our Loan Calculator to model different rate and fee combinations and find the loan that truly costs the least.