Mortgage Rate Locks: When to Lock and What It Protects
A rate lock protects you from market swings while your loan is processed. Learn how locks work, how long they last, and what happens if closing slips.
Mortgage pricing can change daily, sometimes more than once a day. A rate lock is how you take that uncertainty off the table while your loan moves through underwriting. It's one of the most important decisions in the process, and one of the least explained.
What a rate lock is
A lock is a commitment from the lender to honor a specific rate and price for a set number of days. If the market moves against you during that time, your terms stay put. If the market improves, you generally keep the locked terms unless your lock includes a float-down feature.
The lock is tied to your loan details: loan amount, property type, credit score, occupancy, and loan program. If any of those change significantly, the pricing can change too, even during a lock.
How long locks last
Common lock periods run from about 15 to 60 days, and longer locks are available for things like new construction. Longer locks usually cost a bit more, because the lender is carrying the risk longer. The goal is to choose a period that comfortably covers your escrow plus a small cushion.
| Situation | Lock approach to discuss |
|---|---|
| Standard purchase escrow | Lock period that covers the full escrow plus a few days |
| Refinance | Lock once the application is complete and you're comfortable with the terms |
| New construction | Extended lock options, if the completion date is firm |
| Volatile market | Lock earlier rather than waiting for a "perfect" day |
Floating versus locking
Choosing not to lock right away is called floating. Floating can work if you believe the market will improve before closing, but nobody predicts rates reliably, including professionals. I encourage clients to decide based on what they can afford, not on a market forecast. If today's terms work for your budget, locking turns a guess into a plan.
What can disrupt a lock
- Escrow delays. Appraisal timing, repair negotiations, or title issues can push closing past the lock date.
- Changes to the loan. A different loan amount, a lower appraised value, or a credit score change can reprice the loan.
- Slow document turnaround. Missing paperwork is one of the most avoidable causes of lock extensions.
Extensions are often available, but they usually cost something. The best protection is a realistic timeline and fast responses to conditions. My guide on what not to do during escrow covers the habits that keep loans on schedule.
Float-down options
Some lenders offer a float-down, which lets you capture improved pricing if the market moves meaningfully in your favor after you lock. These features vary widely in cost and rules. Ask how much movement is required, when you can exercise it, and what it costs, then decide if it's worth it for you.
Locking on a refinance
Refinances work a little differently than purchases. There's no contract deadline, so the timeline depends on how quickly documents come in, how fast the appraisal is completed, and how busy lenders are. When many homeowners refinance at once, processing times can stretch. Ask your loan officer how long similar refinances are taking right now and choose a lock period with a cushion.
Refinances also have a mandatory three-day right of rescission for primary residences after signing, before the loan funds. Build that into your expected funding date.
Questions to ask before you lock
- What exactly is locked: rate, points, and credits?
- When does the lock expire, and what's the cost to extend?
- What changes would cause the pricing to be adjusted during the lock?
- Is a float-down available, and on what terms?
- Will I get written confirmation of the lock?
Clear answers to these five questions remove most of the confusion around locks.
The takeaway
A rate lock protects your budget from market swings. Lock when the terms work for you, choose a lock period that fits your timeline, and keep your file moving so the lock doesn't expire. Ask your loan officer to put the lock details in writing, including the expiration date, so everyone on your team is working toward the same deadline.
