We’ve spent several Mortgage 101 articles talking about why mortgage rates move, what affects YOUR pricing, and why the rate you’re quoted today may not be the rate available tomorrow.
Which eventually brings us to how you make it stop moving.
You lock it.
A rate lock is basically an agreement between you and the lender that your interest rate will be protected for a specific amount of time while you finish the mortgage process. The rate we’re talking about here is your note rate—the actual interest rate that will eventually be written into your Promissory Note, which is the legal document spelling out what you borrowed and how you’ll repay it.
If your rate isn’t locked, it can change as the market changes. Once it is locked, the lender agrees to honor that rate as long as you close within the agreed-upon lock period and the important details of your loan don’t change.
So far, pretty simple.
Naturally, as we've learned, the mortgage industry can't leave it there. 🙄
How long does a rate lock last?
There isn’t some universal lock period. 30-, 45-, and 60-day locks are typical, although longer options may be available depending on the lender.
The important thing is that you need enough time to actually get your loan closed before the lock expires.
If we expect to close in 35 days and I lock your rate for 30, we already know we'll need a 5-day lock extension (and pay for it, accordingly). If we lock it for 90 days when we have every reason to believe we’ll close in 30, we'd be paying (handsomely) for time we don’t need.
Because longer locks come at a price.
That doesn’t necessarily mean there’s a separate fee with “rate lock” written next to it. Remember everything we’ve already discussed about mortgage pricing: the difference can show up in the cost attached to the interest rate. A longer lock means paying more for the same rate, receiving less lender credit, or otherwise getting slightly worse pricing than you would with a shorter lock.
Exactly how that works varies by lender and there is no universal rule, so all I care about is looking at the actual options available on YOUR loan. The best practice is to simply ask the lender what lock periods are available and what a different length would cost, because your Loan Estimate won’t automatically show you that.
So when should you lock?
This is where people usually want me to predict the future.
I typically tell them that if I had that ability, I'd currently be on a yacht in international waters sipping a mojito.
There's simply no possible way to perfectly answer “Should I lock today or wait?” because waiting means making a tradeoff. If you float—or leave the rate unlocked—you still have the opportunity to benefit if mortgage pricing improves. You also risk getting punched directly in the budget if it gets worse.
So the real question isn’t just, “Do I think rates are going down?”
It’s what happens to YOU if they don’t?
Let’s say the payment at today’s pricing works comfortably for you and we have a lock period long enough to get the loan closed. If rates get worse tomorrow, would it meaningfully change the financial decision? Would it push the payment outside your comfort zone? Could it affect your loan approval?
Those are quite different levels of risk.
I’m way less interested in trying to squeeze every possible eighth of a percent (0.125%) out of the market than I am in understanding what we’re risking in exchange.
Purchase loans make that decision especially important
If you’re refinancing, you usually have some freedom to decide whether the deal still pencils out if rates move against you.
A purchase is different because there’s a house and a contract on the line.
Once you’re under contract, you have a closing date to meet. You may have earnest money (and paid inspection or appraisal fees) at risk. And if rates rise enough to materially change the payment—or your qualification—we may suddenly have a MUCH bigger problem than wishing we’d gotten a slightly better deal.
That doesn’t mean you should panic-lock the second you get a contract. It means we need to fully consider the downside BEFORE we decide to keep floating.
There is a very meaningful difference between “I’m willing to gamble a little because I have plenty of room in my budget” and “If rates move against me, this entire transaction may blow up in my face.”
Those two borrowers should probably not make the same decision.
A rate lock is not a magical force field
Another important little mortgage detail: locking your rate doesn’t necessarily mean nothing about your pricing can ever change.
A rate lock protects the agreed-upon rate based on the loan we priced at the time. If important pieces of that loan change, the pricing may change too.
For example, changing the loan program, down payment, loan amount, or other material information can affect it. Changes to credit, income verification, or the appraisal can also matter depending on the circumstances. The Consumer Financial Protection Bureau (CFPB) specifically warns that a locked rate can still change when significant information changes.
Which makes sense when you think about everything we just covered in the articles about mortgage pricing.
We locked a specific loan.
Change the loan, and we may have just changed its price.
And what happens if the lock expires?
Ideally, we don’t let it.
But mortgages involve appraisals, underwriting, title work, insurance, sellers, buyers, lenders, attorneys in some states, government agencies in some loan programs, and approximately 74 opportunities for somebody to need "one more thing."
Sometimes a loan simply takes longer than expected.
If your lock is about to expire, the lender can typically extend it—but the rules and cost of doing that vary by lender. The CFPB specifically notes that extensions can be expensive and recommends finding out your lender’s policy before you find out the hard way.
The cheapest lock period on day one is not necessarily the cheapest way to get all the way to closing.
What if rates get BETTER after you lock?
Ahhh, yes. The part everybody hates (me included).
A standard rate lock is primarily there to protect you if rates get worse. It does not automatically mean you get to keep the protection when rates rise AND grab the lower rate if rates fall.
I'm able to offer a float-down option or another way to take advantage of improved pricing after you’ve locked, but those are lender-specific policies and vary considerably. There may be rules about how much the market has to improve, when you have that option, or what it costs.
So if that matters to you, ask about it before locking rather than assuming it exists.
So what am I actually deciding when I lock?
You’re not just picking an interest rate.
You’re choosing how much market risk you’re willing to keep between now and closing, and how much time you want the lender to guarantee the rate & pricing you have today.
That’s why my lock conversation isn’t simply, “Rates look good. Lock ’em.”
I want to know how much time we realistically need, what each lock period costs, what happens if the loan takes longer than expected, how much room you have if rates get worse, and whether waiting is actually worth that risk to you.
Because nobody gets extra credit at closing for correctly guessing what the bond market was going to do. And no one has any skin in this game but you.
The goal is to get you to closing with a loan structure you’re happy with—not win a bet against the market.
Source: What's a lock-in or a rate lock on a mortgage?, Consumer Financial Protection Bureau