APR vs. Interest Rate: What's the Difference?

Interest rate is the cost of borrowing the principal. APR (annual percentage rate) is a broader measure that bundles in certain fees, so it's usually higher and is the better number for comparing loans. The gap between them tells you how much you're paying in fees on top of interest. Here's how each is calculated and when the difference matters.

The interest rate is the annual cost of borrowing the principal, expressed as a percentage. On an amortizing loan, each monthly payment is split between interest (rate × remaining balance ÷ 12) and principal. The rate alone doesn't account for origination fees, points, or other upfront costs.

APR expresses the yearly cost of the loan including certain one-time fees — typically origination fees, points, and some closing costs — spread across the term. It gives a more apples-to-apples comparison of total first-year cost. The formula conceptually:

APR ≈ (total interest over 1 year + included fees) / loan amount

If a loan charges a $300 origination fee on $10,000, that fee raises the APR above the stated interest rate even though the rate didn't change. Two loans with the same interest rate but different fees will have different APRs — and the higher APR is the more expensive one.

This first-year expression is only a rough approximation. The APR a lender discloses amortizes the fee across the full loan term, so for a multi-year loan the disclosed APR sits between the interest rate and this first-year estimate. The worked example below uses the full-term calculation.

For many credit cards, the APR and the interest rate are the same because there are no upfront fees. For mortgages, the APR is often meaningfully higher than the rate because of closing costs, discount points, and mortgage insurance. That's why APR is the better number for comparing two mortgage offers, while the rate drives your monthly principal-and-interest payment.

• Use the interest rate to estimate the monthly payment.
• Use the APR to compare the true cost across offers.

Loan A: $20,000 at 8.0% interest, no fees → APR ≈ 8.0%. Loan B: $20,000 at 7.9% interest with a $400 origination fee, repaid over 60 months (5 years). You receive only $19,600 (the $20,000 minus the $400 fee) but repay based on the full $20,000 balance, so the fee pushes the APR up to about 8.8% — higher than Loan A's 8.0%. Loan B's lower rate looks cheaper, but after the fee its APR is higher, so Loan A is the cheaper loan. Always compare APR to APR, not rate to rate: the longer the term, the more a lower rate tends to outweigh a one-time fee; over a short term, a fee can flip which loan is cheaper.