A mortgage rate lock is your lender’s written commitment to hold a specific interest rate for you while your loan closes — usually for 30 to 45 days — so a market move between your offer and your closing can’t change your payment. In a market like late 2026, where the Federal Reserve is openly weighing a September rate increase, the short answer to “should I lock?” is: if you’re under contract and closing within 45 days, locking early almost always beats waiting. Here’s how locks actually work, what they cost, and the questions Central Indiana buyers ask me most.
What is a mortgage rate lock?
When you apply for a mortgage, the rate you’re quoted is a moving target — lenders re-price every business day, sometimes more than once. A rate lock freezes that quote. Once locked, your rate is protected for a set window (typically 15, 30, 45, or 60 days) regardless of what the market does before closing.
Two things surprise people about locks. First, a standard lock usually has no separate fee — the cost is built into the pricing you’re quoted, with longer locks priced slightly higher than shorter ones. Second, a lock protects the lender’s commitment, not just yours: if rates jump half a point the week before closing, your locked rate holds.
The Consumer Financial Protection Bureau’s guidance is worth knowing: your locked rate can generally only change if the lock expires or if something material about your application changes — your credit score, loan amount, down payment, or an appraisal that comes in differently than expected. A lender can’t re-trade your rate just because the market moved.
When should you lock in a mortgage rate?
The honest answer is that nobody times the market reliably — after 30 years of watching rates, the week-to-week moves can still surprise me. So instead of predicting, use rules:
Closing within 30–45 days? Lock at application. The potential savings from floating rarely justify the risk. A quarter-point move on a $300,000 loan changes the payment by roughly $50 a month — for the life of the loan.
Only float with a reason and an exit. If you choose to float, decide in advance what number triggers your lock, and have your loan officer watch it daily. “Float and hope” is not a strategy.
Mind the calendar. Rates move most around scheduled events: Federal Reserve meetings, monthly inflation reports, and jobs reports. Right now the September 15–16 Fed meeting is the event that matters — markets have priced meaningful odds of a rate increase, which is exactly the setup where locking early protects you. As of Freddie Mac’s August 13 survey, the 30-year fixed averaged 6.67% — slightly below the prior week. When the market hands you a dip in front of a risk event, that’s typically a gift worth taking.
You can see where rates sit any weekday on my Current Rates page, which I update every morning.
How long can you lock a mortgage rate?
Standard lock windows are 15, 30, 45, and 60 days; some lenders offer 90 or more for new construction. Pricing improves as the window shortens — a 15-day lock is the cheapest money in the mortgage world, which is why a fully prepared file matters (see how the loan process works).
If your closing slips past the lock expiration, locks can usually be extended for a modest fee, typically a fraction of a point per week of extension. The better plan is matching the lock to a realistic closing date up front — and speed pays here: I consistently close purchase loans in 15 to 30 days unless there’s a reason to wait longer, which often means a shorter, better-priced lock does the job.
What if rates drop after I lock? (Float-downs and renegotiations)
Locking doesn’t always mean you’re stuck if the market moves your way — but the honest version of this answer has more fine print than most articles admit.
Some lenders offer a true “float-down” option; many others instead allow a one-time lock renegotiation. Either way, the common threads are: the market usually has to improve meaningfully (often at least a quarter point versus recent pricing) before you qualify; the loan generally needs to be well along in underwriting; there’s a real cost built into the mechanics; certain products — jumbo and some investor and down-payment-assistance programs — are typically excluded; and it’s a one-time adjustment, not an ongoing re-price. Your lock expiration doesn’t reset, and the total deal generally can’t come out better than what you originally locked — think of it as repair for a big rate drop, not a do-over.
The practical takeaway: lock based on the protection, not on the hope of a later adjustment — and if rates do fall meaningfully after you lock, ask the question. Whether a specific loan qualifies depends on the lender, the program, and where the file sits in underwriting, which is a five-minute check I run for my borrowers whenever the market gives us the chance.
Can the lender change my rate after locking?
Only in specific situations: the lock expires before closing, or the application materially changes — a different loan amount, a credit score shift, a changed down payment, an appraisal surprise. This is also why comparing offers on rate alone misleads: the structure of the quote matters as much as the number. I wrote a companion piece on that: Mortgage Rate vs. APR: What the Lowest Rate Doesn’t Tell You.
How long does a mortgage pre-approval last?
Most pre-approval letters are good for 60 to 90 days, because the documents behind them go stale — pay stubs, bank statements, and credit reports all have shelf lives. In a rising-rate environment, an aging pre-approval carries a second risk: you may have been approved at a payment based on last quarter’s rates.
Two protections I build in for my buyers: refreshing any letter older than 60 days before writing offers, and stress-testing the approval — if a buyer qualifies at 6.5%, I re-run the numbers at 7% so a rate move between offer and closing can’t kill the deal. If you’re early in the process, start with the first-time homebuyer guide.
What this means in Central Indiana right now
The local backdrop makes lock strategy unusually interesting this fall. Per the July MIBOR data, Central Indiana inventory reached roughly 8,000 active listings — the most in nearly a decade — while the median sale price held around $324,000 and homes averaged 21 days on market. Translation: buyers finally have selection and negotiating room, at the same time the rate outlook carries a September risk.
That combination rewards a specific play: negotiate hard on the house (sellers are more flexible than they’ve been in years — including seller-paid temporary rate buydowns), and lock early on the loan. You control the purchase-price conversation; nobody controls what the Fed does on September 16.
Frequently asked questions
Should I lock my mortgage rate today?
If you’re under contract and closing within 45 days, generally yes — especially with a Fed meeting ahead. If you’re still shopping, you usually can’t lock yet (most lenders require a property address), but you can get fully pre-approved so you’re ready to lock the day your offer is accepted.
What happens if rates drop after I lock?
With a standard lock, your rate stays where you locked it — that’s the trade for protection. If the drop is meaningful (typically at least a quarter point versus recent pricing), ask your loan officer whether a one-time float-down or lock renegotiation is available on your specific loan — some lenders and programs allow it with conditions and costs, and some don’t. It’s a repair tool for a big move, not a free re-price.
What if my rate lock expires before closing?
Locks can typically be extended for a fee. If a delay looks likely, tell your loan officer early — a planned extension is cheaper than an emergency one, and sometimes the timeline can be recovered without one.
Does locking a mortgage rate cost money?
A standard-length lock normally has no separate fee; it’s built into your quoted pricing. Unusually long locks and extensions do carry costs. If a quote’s lock terms are unclear, that’s a question worth asking in writing.
Can I switch lenders after locking?
Yes — a lock commits the lender, not you. But switching restarts underwriting and the clock, which has real risk inside a purchase contract’s deadlines. If you’re considering it because another quote looks better, have both offers compared line by line first (I do this for borrowers even when the other quote wins).
Talk through your timing
Every buyer’s lock decision comes down to their contract dates, their risk tolerance, and what the calendar holds — a ten-minute conversation, not a guess. If you’re buying in Indianapolis, Carmel, Fishers, Noblesville, Westfield, or anywhere in Indiana, call or text me at (317) 603-0912 and we’ll map your timing against the market. Realtors: this is exactly the conversation I have with your buyers to keep deals together — more on how I work with agent partners here.
Greg Rank is a mortgage broker at Channelwood Mortgage in Carmel, Indiana (NMLS #138276, company NMLS #129852), licensed in Indiana and Florida. This article is general education, not personalized mortgage advice or a loan offer; rates referenced are from Freddie Mac’s Primary Mortgage Market Survey of August 13, 2026 and change weekly.