APR vs Interest Rate: The Number That Actually Matters
The rate gets your attention. The APR reveals what the loan really costs. Here is why it matters and when to ignore it.
Interest rate and APR are not two ways of saying the same thing. One is an ingredient; the other is the full recipe. If you are comparing lenders, the interest rate is a marketing number. The APR is the regulation-mandated truth-in-lending figure that forces lenders to disclose total cost. But even APR can be misleading if you do not understand what it leaves out. Use our mortgage calculator to model total interest under both rate and APR assumptions.
What Each Number Actually Means
The interest rate is what the lender charges annually on the principal you borrow. A 6.75% rate on a $400,000 loan means roughly $27,000 in interest the first year, declining as you pay down principal through amortization.
The APR is a synthetic rate. It takes the lender fees, pre-paid interest, any points you paid, and mortgage insurance, spreads them across the loan term, and adds that on top of the base rate. A 6.75% rate with $8,000 in closing costs becomes roughly 7.05% APR on a 30-year loan. Think of APR as the total effective rate.
A Practical Example
You apply with two lenders on a $380,000 loan:
| Lender | Rate | Points/Origination | APR |
|---|---|---|---|
| Lender A | 6.75% | 0 points, $2,500 fees | 6.88% |
| Lender B | 6.50% | 1.5 points ($5,700), $3,000 fees | 6.93% |
On the surface, Lender B has the lower rate. But because of the $5,700 in points, the APR is actually higher. If you keep the loan for ten years or more, Lender B saves money because the lower rate overcomes the upfront cost. If you refinance or sell within four years, Lender A is cheaper because you never recouped the points. The break-even on those points is roughly six and a half years. Use our break-even calculator to find the exact crossover for your offer.
When APR Fails You
APR assumes you keep the loan for the full term. Almost nobody does. The average mortgage is refinanced or sold within seven years. If you plan to move or refinance early, the APR overstates the cost of upfront fees. In those scenarios, run an explicit break-even calculation — total interest plus fees over your actual expected holding period — rather than trusting APR blindly.
APR also excludes third-party costs that vary by property or region, like title insurance and transfer taxes, making inter-state comparisons slightly skewed. Always compare APRs within the same loan term, too. A 15-year loan will have a higher APR than a 30-year with the same rate because the fees are compressed into a shorter amortization window.
The Rule of Thumb
Use APR when you are deciding between two lenders on the same loan product. Use interest rate when you are deciding whether to buy points or pay discount fees. Every mortgage decision is a math problem with one right answer for your timeline. Do the calculation before you lock.
New York buyers face a median home price of $428,000 with a 1.40% effective property tax rate. See how these numbers affect your payment with our New York mortgage calculator.
Compare with California (median home price $786,000, 0.74% property tax) using our California mortgage calculator.