A mortgage rate lock is an agreement between you and your lender to close your loan at a specific interest rate within a set period of time. That is the whole definition, and almost everything buyers believe beyond it is a misconception. A quote is a rate lock's opposite; until you lock, the rate a loan officer mentioned on Tuesday means nothing on Friday. Inside any 30-day escrow, rates move enough to change your payment, and if your debt-to-income ratio is tight, a half-percent spike while you float can invalidate your approval outright. So the lock is your protection against volatility, and using it well means understanding lock periods, float-downs, extensions, and what happens when one expires.
Two decisions sit on either side of the lock itself: when to pull the trigger and lock in the first place, and, if rates fall afterward, whether you can renegotiate the rate you already locked.
Lenders generally offer locks in 15-day increments: 15, 30, 45, and 60 days, with longer terms of 90 up to 180 days available from some (but far from all) lenders. A few now price in one-day increments, so a buyer who needs exactly 17 days can lock exactly 17 days.
The rule that governs all of it: the shorter the lock, the better the pricing. The logic is the same one life insurers use. A 10-year term policy on a 50-year-old is cheap because the insurer will probably never pay; a 30-year policy on the same person costs far more. A 180-day lock insures a much longer window of rate risk than a 15-day lock, so the lender charges more for it. The practical takeaways:
Floating means going without the guarantee: if the market improves you win, and if it turns you absorb the damage. Barry Habib, a past guest on the show, is famous for the framing that while you float, only three things can happen to your rate, and two of them are good: rates fall and you benefit, rates hold flat and a shorter lock later gets you slightly better pricing, or rates rise and you lose.
Whether to take that bet comes down to your risk tolerance and your timeline. Ask yourself honestly which Vegas traveler you are: the one feeding a slot machine at the airport before baggage claim, or the one who enjoys the shows and the buffet and never gambles a dollar. A borrower who will lose sleep over a red day in the bond market should lock and stop watching. And ignore anyone confidently forecasting rates months out; if you close in 21 days, the only forecast that matters is the next one to three weeks, which is exactly the window where even professional lock advisories regularly disagree with each other. Mortgage rates also take their cue from the bond market rather than the Fed's meetings, a distinction we unpack in whether the Fed rate affects mortgage rates.
The cost of casual floating is real. A borrower we worked with planned to lock on a Sunday using Friday's pricing, an option our investor allowed. Another lender talked him out of it, insisting weekend locks do not exist (some lenders allow them; many do not) and promising to lock him Monday morning. Monday opened half to three quarters of a point worse. He closed an eighth higher in rate and a half point more in cost than the Sunday lock would have delivered, all from waiting one night. Across 1,300+ closed loans, we have watched almost nobody pick the absolute bottom day to lock. That is the wrong goal. The lock's job is removing the risk that the day you need turns out to be the worst one.
On a purchase, you generally need a property under contract, because the lock is tied to your social security number and a specific address. On a refinance, you can lock whenever you commit to moving forward. Lock-and-shop programs that let you lock before finding a home do exist, but they carry worse pricing, because lenders hedge every lock in the secondary market and locks without a property fall through far more often. On the other end, the deadline: your rate must be locked when your closing disclosure goes out, which happens at least three business days before you sign.
(The policy figures that follow, on extension fees, relock costs, and float-down thresholds, reflect common lender policies as of this episode, 5/21/2024. Every lender writes its own rules and they change; confirm current terms before you lock.)
For a normal lock under 90 days, there should be no upfront fee; the cost of the lock is built into the pricing you are quoted. Long-term locks are the exception. On new construction needing 180 days, some lenders take an upfront deposit that works like a restaurant holding your credit card for a reservation: show up and close, and it is credited back to your transaction; ghost the lender, and they keep it, because hedging your lock cost them real money.
A related question we get: can you lock with two lenders at once? You can, and you should not. Both lenders carry hedging costs on your lock, and one of them is working for free. If you feel you need a backup lender, say so openly to both and let them decide, rather than running two full processes in secret and dropping one at the closing table. Do the comparison honestly up front: same day, same lock term, same program, then commit.
This is the question behind most lock anxiety, and the answer is more forgiving than people expect. A lock means your terms cannot get worse. If the market improves substantially, most lenders offer a float-down, also called a renegotiation, that captures much of the improvement, though never all of it, because the lender already paid to hedge your original rate.
Typical shape of these policies: the market generally needs to improve at least a quarter percent (the friendliest programs trigger at an eighth), and the renegotiation itself costs anywhere from about 0.375 to a full point in pricing. The bigger the move, the more of it you keep: a rate drop of a full percent might net you around 80% of the improvement, while a drop of three eighths might net roughly half. So the borrower who locks and then watches rates slide is usually not stuck; they are having a float-down conversation. Ask any lender about their float-down policy before you lock, because the policy you locked under is the one you will live with.
Deals run long. A seller delays the appraiser, a document straggles, a signing slips a week. When the closing date threatens to pass your lock expiration, the move is a lock extension, arranged before the lock dies. A 14-day extension commonly runs a quarter to a half point, and who pays should follow who caused the delay: if the seller cost you two weeks, your agent can negotiate for the seller to cover the extension; if the lender dropped the ball, the lender should eat it; and many investors will grant a short extension of two to seven days free when the market has been stable.
Letting a lock expire outright is the outcome to avoid. Relocking after expiration costs roughly an eighth to a quarter point even when pricing has improved, and if pricing has worsened you relock at the worse of the two markets. Lenders also close the obvious loophole: you cannot let a lock lapse and re-lock at a better market the next morning, since most require a lock to be expired around 30 days before you can relock at current pricing with no penalty. Occasionally expiring on purpose is the cheap move (we have taken a 0.1-point relock instead of a 0.2-point extension when the math favored it), but that is a calculation your loan officer should be running for you, and this is exactly the kind of positioning we work through with clients on a Roadmap call: the rate together with the lock strategy that fits your timeline and your risk tolerance.
One more expiration-adjacent question: if your purchase falls apart mid-escrow, can the lock transfer to the next house? Nine times out of ten, no. The lock is hedged against a specific transaction. A few investors will accommodate a transfer when the timeline and loan are similar, and asking costs nothing, but plan on a new lock with the new property.
Never assume a quoted rate is a locked rate. Two documents prove it. A prudent lender sends a lock agreement stating the rate, the cost, the program, and the expiration date. And federal disclosure rules require a fresh Loan Estimate when your loan goes from floating to locked; page one states plainly whether the rate is locked and through what date. If a Loan Estimate shows up marked locked and you never had that conversation, call your loan officer the same day.
Those same rules are why the old bait-and-switch, a 7% quote that becomes 7.5% and a point at the closing table, no longer works. Once locked, your rate and the lender's charges for it cannot change outside a valid change of circumstance: a credit report that expires and repulls with a lower score, an appraisal that comes in low and moves your loan-to-value, or a program switch, like moving from FHA to conventional, which is a new lock at current market. Keep your file boring between lock and closing and the rate you locked is the rate you sign.
Stop guessing what you can really afford
Tell Josh and his team your situation, and you'll get the exact price range you qualify for, the loan that gets you the most home for your money, and a step-by-step plan to close. They handle your loan directly, never a referral, and go far beyond a basic pre-approval, so you stop second-guessing, tour with confidence, and write offers sellers take seriously.
Build my Roadmap →It guarantees your interest rate and the pricing tied to it through a specific expiration date, provided your loan closes by that date and nothing material changes in your file. It protects you from rates rising during escrow. It does not automatically give you a lower rate if the market improves; that requires a float-down, which most lenders offer when rates drop enough, at some cost.
For typical locks under 90 days there is no upfront fee; the lock's cost is embedded in your quoted pricing, and shorter lock periods price better than longer ones. Extended locks of 90 to 180 days, common with new construction, sometimes require an upfront deposit that is credited back at closing if you complete the loan. Policies vary by lender, so confirm before you lock.
On a purchase, you can generally lock once you have a property under contract, and you must be locked before your closing disclosure goes out three business days ahead of signing. Between those points, the decision rides on your risk tolerance and the next one to three weeks of market risk, never on anyone's three-month forecast. If a rate spike would strain your qualification or your sleep, lock early and stop watching.
Ask your lender about a float-down or renegotiation. Most programs require the market to improve at least a quarter percent from your locked terms and charge roughly 0.375 to a full point for the renegotiation, so you capture most of a large improvement but never all of it. A drop of a full percent might net you around 80% of the move. Ask about the policy before locking, since it varies widely.
Relocking an expired lock typically costs an eighth to a quarter point even when pricing improved, and if pricing worsened you relock at the worse market. Most lenders will not let you relock at current market for free until the old lock has been expired around 30 days. The better path is extending before expiration, which runs about a quarter to a half point for two weeks, ideally paid by whoever caused the delay.
You should have a lock agreement showing the rate, cost, program, and expiration date, and federal rules require an updated Loan Estimate whenever your loan moves from floating to locked. Check page one of the Loan Estimate: it states whether the rate is locked and through what date. A verbal quote is never a lock, so if you have not had an explicit lock conversation, assume you are floating.