The Number on Your Mortgage Lock Letter Is Not the Rate You're Actually Paying

When a lender tells you they've locked in your rate at 6.75%, it feels like a finish line. You have a number. You can plan around it. You can tell your friends and family what your mortgage rate is, and it sounds definitive.

Except that number — the one printed on your lock confirmation — is not actually the rate you're paying to borrow money. It's closer to a starting point than a final answer.

What a Mortgage Rate Actually Measures

The rate on your lock letter is called the note rate, and it's the base interest percentage applied to your loan balance. It determines your monthly payment calculation. But it says almost nothing about the true cost of borrowing, because it doesn't account for the fees you paid to get that rate in the first place.

This is where mortgage points enter the picture, and most borrowers don't fully understand what they're agreeing to.

A mortgage point equals one percent of your loan amount. Paying one point on a $400,000 loan means handing over $4,000 at closing. In exchange, your lender reduces your note rate — typically by around 0.25%, though this varies by lender and market conditions. Borrowers who want a lower monthly payment often pay points upfront without fully calculating whether that tradeoff actually saves them money over time.

That $4,000 you paid to shave a quarter percent off your rate? It takes years to recoup through lower monthly payments. If you sell or refinance before that break-even point — which, statistically, a large share of American homeowners do — you spent money you never got back.

The Number That Actually Tells the Truth

There is a more honest figure buried in your loan documents: the Annual Percentage Rate, or APR. Federal law requires lenders to disclose it, and unlike the note rate, the APR folds in origination fees, points, mortgage broker fees, and certain closing costs. It reflects what you're truly paying on an annualized basis to access that loan.

The gap between a loan's note rate and its APR can be surprisingly wide. A mortgage advertised at 6.75% might carry an APR of 7.1% once fees are factored in. That difference isn't trivial over 30 years.

And yet most borrowers never compare APRs between lenders. They compare note rates, because note rates are what get advertised, what get quoted over the phone, and what feel most tangible. Lenders know this. Advertising a 6.625% rate is more compelling than explaining that the APR is 7.05%.

Adjustable Rates Add Another Layer of Uncertainty

Fixed-rate mortgages at least give you a stable note rate for the life of the loan. Adjustable-rate mortgages — ARMs — introduce a different kind of complexity that borrowers often underestimate.

A 5/1 ARM gives you a fixed rate for the first five years, then adjusts annually based on a benchmark index plus a margin set by your lender. The initial rate on an ARM is almost always lower than a comparable fixed rate, which makes it attractive on paper. But the rate you locked in is only guaranteed for that initial period. After that, it moves — and depending on where interest rates are heading, it can move significantly.

ARMs aren't inherently bad products. For someone who knows they'll sell or refinance within five years, a 5/1 ARM can genuinely be the cheaper option. The problem is that most people who take ARMs don't have a clear exit strategy. They locked in a rate that felt real, without fully internalizing that the rate has an expiration date.

Why This Misconception Is So Persistent

The mortgage industry has spent decades making the note rate the central figure in the conversation, and there are structural reasons for that. A lower note rate is easier to advertise than a more complicated APR comparison. Loan officers are often compensated in ways that reward closing loans quickly rather than ensuring borrowers fully understand the cost structure.

There's also a psychological element. Closing on a home is stressful and document-heavy. By the time most buyers are staring at their final loan disclosure, they've already committed emotionally and practically to the purchase. The motivation to scrutinize fee structures is low when you're exhausted and just want to get to the closing table.

And the rate lock itself creates a false sense of certainty. The phrase "locking in" implies security and finality. What it actually means is that your note rate won't change before closing — not that your total borrowing cost is settled.

What to Actually Compare Before You Sign

If you're shopping mortgages, the APR is a far more useful comparison tool than the note rate alone. Ask every lender for a Loan Estimate — a standardized three-page document that federal regulations require lenders to provide. It lays out the APR, total loan costs, and monthly payment in a format designed for side-by-side comparison.

Also worth calculating: your break-even point on any points you're being asked to pay. Divide the upfront cost of the points by your monthly savings to find out how many months it takes to come out ahead. If that number exceeds how long you realistically expect to hold the loan, paying points doesn't make financial sense regardless of how good the rate looks.

The note rate is a real number. It's just not the whole story. And in a transaction as large as a home purchase, the whole story is the one worth reading.

The takeaway: The rate on your mortgage lock letter is a starting point, not a final answer. The APR, the points you paid, and the loan structure you chose all determine what borrowing actually costs — and those numbers deserve as much attention as the headline rate.