A mortgage rate lock is a lender’s written commitment to hold your interest rate for a set period of time while your loan moves through underwriting and closing. Lock periods typically run 15 to 60 days, some lenders offer a one-time float-down if rates drop after you lock, and if your closing runs past the lock expiration, you’ll either pay an extension fee or re-lock at whatever pricing is available that day. I walk almost every client through this conversation, because the lock decision — not just the rate itself — is often what determines whether their closing feels calm or chaotic.
What a Mortgage Rate Lock Actually Does
Without a lock, your rate floats with the market every single day until you close. That’s fine if rates are stable, but it’s a real risk on a purchase with a tight timeline. Once you lock, the lender guarantees that rate (and usually the points associated with it) through the lock expiration date, regardless of what happens in the broader bond market in the meantime. It doesn’t protect you from changes to your own file, though — if your credit score drops, your income documentation changes, or the appraisal comes in low, the loan terms can still shift. A lock is a pricing commitment, not a blanket guarantee that nothing else about the loan will move. If you want the bigger picture on why your quote differs from what you see nationally, I’ve written about why mortgage rate quotes won’t match the national average and what determines your mortgage rate — both get into how your specific file interacts with market pricing.
How Long Lock Periods Typically Last
Most lenders offer a menu of lock periods, and pricing usually gets slightly more expensive as the period gets longer, since the lender is carrying more risk the longer they hold your rate.
- 15-day locks: the shortest window, used when closing is imminent and all underwriting conditions are cleared; because the lender is carrying less risk over such a short period, this option generally doesn’t add much cost.
- 30-day locks: the most common choice for a standard purchase or refinance timeline.
- 45-day locks: useful when there’s a contingency, a slower title process, or a new-construction file with some buffer built in.
- 60-day (or longer) locks: common for new construction or when a seller’s move-out date pushes the closing further out; these cost more in rate or points.
In my experience, the mistake I see most often is a buyer locking for 30 days on a file that realistically needs 45 — maybe there’s an HOA document delay in a Phoenix condo deal, or a second appraisal review on a Denver property. Padding the lock period by a couple of weeks usually costs less than scrambling for an extension later.
Float-Down Options: Getting a Better Rate After You Lock
Some lenders, including on certain Loanatik programs, offer a float-down provision — a one-time option to re-price your locked rate downward if market rates move favorably before you close. It’s not automatic and it’s not available on every program, so ask specifically whether your loan includes it before you assume it’s there. Typically there’s a minimum improvement threshold (say, market rates need to move enough to matter) and a fee or slightly higher starting rate to buy the feature in the first place. Here’s a simple example: say you lock a 30-year rate in March, and six weeks before closing on a new-construction home the market pricing improves. With a float-down clause, you can request the lender re-set your rate to the improved pricing instead of being stuck at the original lock. Without it, you’re at the original number no matter which direction the market moves. If you’re weighing whether paying for points or a float-down feature is worth it for your situation, our piece on mortgage points and rate buydowns walks through that math.
Curious what pricing and lock options look like for your file? Check current mortgage rates and talk to a loan officer about which lock period fits your closing timeline.
What Happens If You Blow the Lock
“Blowing the lock” just means your closing didn’t happen before the lock expiration date. It happens — appraisals get delayed, a seller needs an extra week, title work hits a snag. When it does, you generally have two options:
- Pay for a lock extension. Most lenders charge a fee (often expressed in basis points of the loan amount) to extend the existing rate for a short additional window, commonly 7 to 15 days.
- Re-lock at the rate available when you re-lock. If the delay is longer or the lender doesn’t offer an extension on your program, you re-lock at whatever rate is available on that day — which could be better or worse than your original lock, since rates move in both directions.
Whose fault it is matters here. If the delay is on the lender’s side — slow underwriting, for instance — many lenders will absorb the extension cost rather than pass it to the borrower. If the delay traces back to the buyer or a third party (a late appraisal request, missing documents, a seller pushing the closing date), the extension fee is more likely to land on the borrower. Ask your loan officer directly how extension costs get allocated before you’re staring down an expiration date with no good options.
Locking on a Refinance vs. a Purchase
The mechanics are the same, but the stakes feel different depending on which side you’re on. On a purchase, your closing date is tied to a contract with a seller, so a blown lock can threaten the whole transaction. On a refinance, you usually have more flexibility — if the lock expires, you can typically just restart the process without losing a house. That said, refinance timelines get stretched by the same things: appraisal scheduling, title searches, and payoff statements from your current lender. If you’re trying to decide whether refinancing even makes sense before you worry about lock mechanics at all, start with our refinancing basics guide, which covers the break-even math most people skip.
A Few Things to Ask Before You Lock
Before you sign a lock agreement, I’d want clear answers on:
- What’s the lock period, and does it realistically cover your expected closing date with some buffer?
- Is a float-down available, and what does it cost or require?
- What’s the extension fee structure if the closing slips?
- Does the lock cover points and credits, or just the base rate?
The Consumer Financial Protection Bureau has a useful plain-language overview of rate locks and how they interact with your Loan Estimate, which is worth a quick read if you want the regulatory framing: CFPB’s explanation of rate locks.
FAQ: Mortgage Rate Lock Questions
Can I lock before I have a signed purchase contract?
Generally no — most lenders require a property address and an executed contract before locking, since the lock is tied to a specific loan amount and property.
Does locking cost anything upfront?
Standard lock periods are usually built into your rate at no separate charge; longer lock periods or float-down features may carry a fee or a slightly higher starting rate, which varies by lender and program.
What if rates drop sharply after I lock and I don’t have a float-down?
Without a float-down provision, you’re generally held to your locked rate. Some borrowers in that position look at a refinance down the road instead, once the loan has closed and seasoned.
This article is general education, not financial advice or a commitment to lend. Loan programs, terms, and availability are subject to credit approval and may change. Loanatik LLC is an Equal Housing Lender. See our licensing & disclosures.