A mortgage rate lock is a written agreement in which your lender freezes your interest rate, and the discount points tied to it, for a set number of days while your loan moves through underwriting to closing. If market rates rise during that window, you keep the lower rate you locked in. If they fall, you’re generally stuck with what you agreed to unless you paid for a float-down. Getting the length and terms right matters, because a lock that’s too short, too long, or misunderstood can cost hundreds or thousands of dollars at the closing table.
How a Rate Lock Works
When you lock, the lender commits to honoring a specific interest rate and point structure for a defined period, no matter what happens in the bond market. It’s a price guarantee with an expiration date.
The alternative is a floating rate. Until you lock, your rate moves with the market every day. That can help during a sustained decline, but it also means the rate could jump on the morning of your closing. Most borrowers lock at some point before closing to take that risk off the table.
When You Can Lock and What It Costs
The earliest lock point depends on the lender. Some will lock as soon as you’re pre-approved. Others wait until a seller has accepted your offer, and a few won’t lock until the appraisal is back and underwriting has begun. Lock too early and the lock may expire before closing; lock too late and you carry rate risk right up to the wire.
Before issuing a lock, a lender generally needs a completed application with verified income, assets, and credit, plus a selected loan program. Conventional, FHA, and VA loans each price differently, and switching later can force a repricing. Settle the financial picture before you pull the trigger.
Most initial locks don’t carry a separate out-of-pocket fee; the cost is built into the rate. When a lender does charge an explicit lock fee, it usually runs between a quarter and a half percent of the loan amount. Whether that fee is refundable depends on the lender’s policy and whether the loan closes.
Choosing the Right Lock Period
Lock periods commonly range from 30 to 120 days, with 30, 45, 60, and 90 days the most widely offered.1Bankrate. Guide to Mortgage Rate Locks: Definition, How It Works Pick a length that matches a realistic estimate of your closing timeline, plus a small cushion.
Longer locks cost more. A 60-day lock typically carries a slightly higher rate or more points than a 30-day lock quoted the same day, because the lender is holding market risk for twice as long. The difference looks small on the rate sheet, but over 30 years even an eighth of a point adds up. Straightforward purchase with a responsive lender? A shorter lock saves money. Title complications, renovation approvals, or a co-op board in the mix? A longer lock is cheaper than an extension.
What Can Cause a Locked Rate to Change
A locked rate isn’t unconditional. Certain changes to your file give the lender grounds to reprice, even mid-lock.2Consumer Financial Protection Bureau. What’s a Lock-In or a Rate Lock on a Mortgage? The common triggers:
- Loan amount or down payment changes. If you put less down or borrow more, the rate tied to your original loan-to-value ratio may no longer apply.
- Appraisal surprises. A value that comes in higher or lower than expected changes the LTV, which affects pricing.
- Switching loan programs. Moving between conventional, FHA, and VA reprices the whole deal.
- Credit score shifts. A significant drop during the lock period lets the lender reevaluate.
Anything that changes the loan’s risk profile is a legitimate reason for the lender to revisit the number. That’s why the safest posture between locking and closing is to change nothing: no new credit accounts, no big purchases, no job moves.
What Your Loan Estimate Should Show
Federal law requires the lender to state on your Loan Estimate whether your rate is locked or floating, and to give the exact date and time the lock expires.3Consumer Financial Protection Bureau. Content of Disclosures for Certain Mortgage Transactions (Loan Estimate) – 1026.37 The disclosure must also say that the rate, points, and lender credits can still change if the rate hasn’t actually been locked yet.
If the initial Loan Estimate went out before you locked, the lender must send a revised Loan Estimate within three business days of the lock, showing the fixed rate, points, and any rate-dependent charges.4eCFR. 12 CFR 1026.19 – Certain Mortgage and Variable-Rate Transactions Read it against what your loan officer quoted. If anything is off, raise it that day, not at closing.
Extending a Lock That’s About to Expire
If closing gets pushed past your expiration date, the guaranteed rate is gone and you’re exposed to whatever the market is doing that morning. A rate that has risen since you locked can push your monthly payment up, drive your debt-to-income ratio past the lender’s limit, and put the approval itself at risk.
To prevent that, request an extension before the original lock expires. Extensions are typically offered in roughly 15-day increments. The cost usually runs between 0.125% and 0.25% of the loan amount per extension, and some lenders charge more for longer ones. On a $400,000 loan, that’s about $500 to $1,000 per extension.
Who pays often depends on who caused the delay. If the holdup was the lender’s processing backlog or a third-party vendor like the appraiser, many lenders will waive or reduce the fee. If you were late with documents or changed loan terms, expect to pay the full amount. Some lenders cap extensions at three, whatever the reason.
If the lock expires without an extension, the lender re-locks at the current market rate. When rates have risen, you get a worse deal. When they’ve fallen, you may come out ahead, but that’s a gamble, not a plan. The math on paying an extension fee is straightforward: compare the fee to the extra interest you’d pay over the life of the loan at today’s rate.
Float-Down Options
A float-down provision gives you a locked ceiling rate while preserving the chance to capture a lower rate if the market drops before closing. It isn’t free.
These agreements generally require rates to fall by a minimum amount, commonly at least 0.25%, before you can exercise the option. Smaller dips don’t count, and you keep the original locked rate. The cost is either an upfront non-refundable fee or a slightly higher starting rate than a standard lock would carry.
Whether a float-down is worth it depends on the market and your timeline. In a genuinely declining rate environment with a long closing window, the feature can pay for itself. In a flat or rising market, you’re paying for insurance you’ll never use. Refinances and purchases with 60-day-plus closings tend to get the most value, simply because there’s more time for rates to move.
Extended Locks for New Construction
Building a new home breaks the standard 30-to-60-day model. Several lenders offer extended locks with durations of 120, 180, 270, or even 360 days to cover the months between breaking ground and moving in.5Bank of America. Builder Rate Lock Advantage
Extended locks cost noticeably more than standard ones. The structure typically involves an upfront lock-in fee, part of which may be credited toward closing costs if the loan closes. If the loan falls through, refund policies vary, and some lenders return the fee only if specific conditions are met and documentation is submitted on time. The rate itself is usually higher too, reflecting the extra months of risk the lender is carrying.
The decision comes down to comparing the extended-lock cost with the risk that rates rise during the build. If rates climb a full percentage point over a year-long build, the fee paid for itself. If they stay flat or drop, you overpaid. Construction delays are common, so building extra time in beyond the expected completion date is worth the incremental cost.
Canceling or Switching Lenders
You can walk away from a rate lock at any time. Locking doesn’t legally require you to close with that lender, so if a competitor offers better terms, you’re free to switch. A lock isn’t transferable, though, so you’d start the process over with the new lender.
Most lenders don’t charge a cancellation penalty, though some impose a waiting period before they’ll let you lock again on the same property. If you paid an upfront lock deposit, refundability depends entirely on the lender’s policy. Read the fine print in the lock agreement before putting money down.
Tax Treatment of Lock-Related Fees
Discount points paid at closing to buy down your rate are generally deductible as mortgage interest if you itemize and meet the IRS requirements.6Internal Revenue Service. Topic No. 504, Home Mortgage Points The IRS separates deductible points from non-deductible loan costs: appraisal fees, mortgage insurance premiums, notary fees, and points charged in place of those administrative costs are not deductible.
Rate lock extension fees and lock deposits sit in a gray area. IRS guidance on mortgage points doesn’t address them directly. If a lock fee functions as prepaid interest that reduces the rate, it may qualify. If it’s really an administrative charge to hold pricing, it likely doesn’t. When the fees are substantial, a tax professional’s advice is worth the cost.