Mortgage Rate Lock Explained: Timing, Float-Downs, and Delayed Closings

A rate lock is a promise from your lender that your interest rate will not change before closing, as long as you close on time and nothing about your application changes.

That second half is where buyers get caught. The lock protects you from the market. It does not protect you from a closing that slips past the date or a file that changes.

Here is how locks work, how I help buyers time them, and what to do when a closing date moves, which happens more than anyone likes, especially with new construction.

How a rate lock works

When you lock, the lender guarantees a specific rate and pricing for a set number of days. If rates rise during that window, your rate holds. If rates fall, your rate usually holds too, unless you have a float-down option.

The Consumer Financial Protection Bureau explains that locks are typically available for 30, 45, or 60 days, and sometimes longer, and that the rate can still change if your application changes. That includes your loan amount, credit score, verified income, down payment, or the appraisal.

So after you lock, keep your file quiet. Do not open new credit, finance furniture, change jobs, or move large sums of money without talking to your lender first.

Floating versus locking

Until you lock, you are floating. Your rate moves with the market.

Some buyers float hoping rates will drop before closing. That is a bet, and nobody can reliably call rate moves week to week, including me. The market is the market.

My general advice is to lock once you have an accepted offer and a realistic closing date, and the payment works for your budget. If rates fall later, you may have options like a float-down or a refinance down the road. If rates jump and you floated, there is no undo. Interest rates and your buying power in Lafayette shows how much a rate change can move a monthly payment.

Matching lock length to your closing timeline

This is the most practical decision in the whole process. A lock that is too short risks an expensive extension. A lock that is too long can cost more up front.

Here is how I think about it with buyers in Greater Lafayette.

• Start with the closing date in the purchase agreement. Count the days from when you plan to lock.
• Add a cushion. Appraisals, repair negotiations, title questions, and underwriting conditions all take time. A few extra days of lock is cheaper than an extension.
• Consider the season. In busy months, appraisers, inspectors, and title companies can run behind.
• Consider the property. Rural homes with wells and septic, homes that need repairs before closing, and unusual properties tend to take longer.

The CFPB guide to reviewing Loan Estimates points out that the top of page one shows whether your rate is locked and until when. It also suggests asking how many days you have to close, what other lock periods are available, and how pricing changes with each one. Those are exactly the right questions.

If you have not picked a lender yet, getting fully pre-approved first makes all of this faster. Pre-approval versus pre-qualification explains the difference.

Float-down options

A float-down lets you take advantage of a rate drop after you lock. It sounds like the best of both worlds, and sometimes it is.

Read the details, because they vary a lot by lender.

• Some lenders charge for it up front, and some build it into pricing.
• Many only allow it if rates fall by a minimum amount.
• It often can only be used once, and only within a certain window before closing.
• Some lenders do not offer it at all.

Ask for the float-down terms in writing and do the math. If you would pay for it, compare that cost to what you would actually save if rates dipped modestly.

What happens when closing slips

Closings move. A repair takes longer than planned, an appraisal comes back late, a title issue needs clearing, or the seller needs more time.

If your closing moves past your lock expiration, you generally have a few paths.

• Extend the lock. Many lenders offer extensions for a fee, often priced by the day or in blocks of days.
• Relock at current rates. If rates have gone up, that costs you. If rates have gone down, it may help, depending on the lender's policy.
• Negotiate who pays. If the delay is on the seller's side, the extension cost is something we can ask the seller to cover in an amendment.

The CFPB suggests asking, before anything goes wrong, what happens if you cannot close in time, whether there is an extension fee, and whether the lender could decline to extend. I ask buyers to get those answers at the start so a delay is an inconvenience instead of a crisis.

My job is to keep the calendar honest. I watch every deadline in the contract, and when something starts to slide, I let you and your lender know right away. What happens at closing in Indiana covers the steps that have to line up in those final weeks.

New construction needs a different plan

New builds are where rate locks get hard. Construction timelines stretch for weather, materials, inspections, and crews, and a completion date that looked firm in spring can move by weeks.

Here is how buyers usually handle it.

• Extended locks. Some lenders offer longer locks for new construction, often at a higher cost or with an upfront deposit.
• Floating until close to completion. Some buyers wait until the builder can commit to a firm date, then lock. That saves lock costs and accepts rate risk.
• Builder lender incentives. Builders sometimes tie extended locks or buydowns to their preferred lender. Those can be worth real money, and I still suggest getting an outside quote to compare.

Ask the builder how firm the completion date is and what happens under the contract if it slips. The new construction buying process in Tippecanoe County covers that contract in detail, and seller concessions and rate buydowns explains how builder incentives can lower your rate.

Locally, I keep an eye on which communities are moving quickly and which are running behind. That is the kind of thing you cannot see on a builder's website, and it matters when you are deciding how long to lock.

Questions to ask your lender before you lock

Bring this list to the conversation. Every lender handles locks a little differently, and the answers matter more than the headline rate.

• When do you usually lock, and can I lock earlier or later?
• What lock lengths do you offer, and how does the price change for each?
• Is there a fee to lock, and is any of it refundable?
• Do you offer a float-down, and what are the exact terms?
• What does an extension cost, and would you ever refuse one?
• What would cause my locked rate or price to change?

Write the answers down, or better yet, ask for them by email. When a closing date moves at the last minute, you will be glad you have them in writing.

How this fits into Buy & Move Smart

In Buy & Move Smart, locking your rate is part of getting your numbers right before you tour and before you write. We line up the closing date, the lock period, and your move so they support each other.

For relocating buyers with a job start date, that matters even more. A slipped closing can mean an extension fee plus extra nights in temporary housing.

The short version

Lock once you have an accepted offer and a realistic closing date. Choose a lock period that covers that date with room to spare. Ask about float-down terms and extension costs before you need them. Keep your credit and finances steady until closing. And on new construction, plan for the date to move.

If you are getting close to writing an offer and want help lining up the timeline, book a time on my calendar. We will map it out together.

A real person reads every message. No pressure either way. Let's get you home.