Mortgage rate locks: timing, costs and questions before closing

"Should I lock now or wait?" is the one mortgage question everyone asks and nobody can answer with a forecast. So don't answer it with a forecast.

Answer it with the same test we give Las Vegas borrowers every week: does the payment work, and does the lock cover your closing date?

This guide covers what a mortgage rate lock actually covers and what 30 to 90 day lock periods cost.

It also covers when a float-down is worth paying for, what really happens when a lock expires, and the exact dollars-and-cents cost of floating into a higher rate.

What is a mortgage rate lock, and what does it actually cover?

A mortgage rate lock (the CFPB calls it a "lock-in") is your lender's commitment that your interest rate won't change between the offer and closing. That commitment holds as long as you close within the specified time frame and there are no changes to your application. Two details in that sentence do all the work:

“A lock-in or rate lock on a mortgage loan means that your interest rate won't change between the offer and closing, as long as you close within the specified time frame and there are no changes to your application.”Consumer Financial Protection Bureau, “What's a lock-in or a rate lock on a mortgage?” consumerfinance.gov

Specifically, it locks the rate-and-points combination, not just the rate. Every rate quote is really a pair: an interest rate plus the discount points (an upfront charge to lower the rate) or lender credit attached to it. In short, a lock freezes that pair. Lender pricing moves daily, sometimes hourly, and without a lock both halves of your quote float with it.

It only holds if your file holds. A lock protects you from the market, not from your own application. Change the loan amount, the program, the property type, your documented income, or have the appraisal come in short, and the lender can re-price the locked deal. That's not fine print malice; the lock was priced for the file you presented.

Your paper trail

Your paper trail matters here.

The Loan Estimate is the standard form the CFPB requires lenders to deliver within three business days of your application.

It states whether or not your rate is locked.

What it does not show, as the CFPB points out, is what an extension would cost or what you're paying for your specific lock period.

Therefore, ask both questions before you sign, and get the lock terms in writing.

The Federal Reserve's consumer guide gives the same advice: get the lock-in agreement in writing.

How long should you lock, and what do longer lock periods cost?

Per the CFPB, rate locks are typically available for 30, 45, or 60 days, and sometimes longer.

The Federal Reserve's consumer guide sketches the fuller menu: some lenders offer short locks of about 7 days after approval, and some go up to 120 days.

As a general pattern across lenders: the longer the lock period, the more it usually costs.

The cost shows up either as an explicit fee (flat, or a percentage of the loan amount) or baked into slightly higher pricing, a few basis points at a time. One basis point is 0.01% of the loan amount.

For scale: 25 basis points of price on a $400,000 loan is $1,000. Every figure here is illustrative, and every lender prices lock periods differently.

Matching the period to your closing timeline

The right lock period isn't the cheapest one. It's the one that covers your realistic closing date with a cushion.

A 30-day lock on a 40-day escrow isn't a bargain; it's a scheduled extension fee.

Ask your loan officer how long files like yours are actually taking to close. Appraisal turn times and underwriting queues vary through the year, so lock past that date, not up to it.

Should you lock now or float?

Floating means leaving your rate unlocked and hoping pricing improves before you must lock. Here's the honest frame: when you float, you're not "waiting for information." You're making a bet on rate direction with your housing payment as the stake. And the stake is bigger than it looks:

A test that beats forecasting

So use a test that doesn't require predicting the future:

Above all, lock when the payment works. If the principal-and-interest payment at today's rate fits the budget you built (our how-much-house-can-you-afford guide shows the 28/36 math), and your lock period covers your closing date, lock. A lock removes the risk of rising rates for the lock period, as long as your application doesn't change. If rates fall a lot after closing, refinancing may let you take a lower rate later, though a refinance has its own costs and you must qualify again.

Float only with cushion and a stomach for it. Floating is defensible when the payment works even at a meaningfully higher rate, you're weeks away from needing the lock anyway, and you'd genuinely shrug at a quarter-point move against you. If a 0.25% rise would break your budget or your nerve, floating is not for you. Lock and go live your life.

What is a float-down, and when is it worth paying for?

A float-down option bolts onto a rate lock and fixes the lock's one emotional flaw: the fear that rates drop the day after you commit. With a float-down, if market pricing improves while you're locked, you get one chance to reset your locked rate to the better market, and if rates rise instead, your locked rate generally still applies, subject to the lock terms. Float-down terms, fees and eligibility vary by lender.

What float-downs cost

Of course, options like that are never free. Here is the typical structure. All of it varies significantly by lender, so treat it as a map, not a menu:

The cost, the trigger, the mechanics

The cost. You pay for a float-down either as an upfront fee, as slightly higher pricing on the locked rate itself (a few basis points, the mirror image of buying points), or both. Some lenders only attach float-downs to longer locks or specific programs.

The trigger. Specifically, most float-down provisions require the market to improve by a minimum amount from your locked rate before you can exercise. Illustratively, that is commonly around a quarter point. A drift of a few basis points doesn't qualify; the option exists for real moves.

The mechanics. Usually exercisable once, usually at the lender's current pricing for your remaining lock period, and usually before a cutoff, often a set number of days before closing. Miss the window and the option quietly expires.

When it's worth it: long locks, jumpy markets, and thin budgets.

On a 90-day new-construction lock, a float-down is close to standard equipment. A lot can happen in 90 days, and the option's price is small next to the lock deposit.

On a 30-day lock in a quiet market, you're often paying real money for a trigger that's unlikely to be hit. Putting the same dollars toward discount points, a rate reduction you get with certainty, can be worth comparing against an option you may never use.

Price both and compare.

What happens if your rate lock expires before closing?

Closings slip. Appraisal backlogs, underwriting conditions, seller delays and title surprises don't care about your lock's expiration date. When the calendar wins, events unfold in a fixed order:

First, the extension. Before a lock dies, your lender will typically offer to extend it for a fee.

For example, it is commonly quoted as a fraction of a point of the loan amount per block of extra time (a week, ten days, fifteen days), and the price varies by lender.

Illustratively: a 15-day extension at 0.25% of a $400,000 loan is a $1,000 one-time charge.

Compare that to the alternative from the worked example above: relocking a quarter point higher costs $66 a month for 360 months.

So when the delay is short, a reasonable extension fee can cost less than relocking at a higher rate, depending on the delay and your lender's pricing. Compare the two in dollars before you decide.

How much does a rate lock extension cost?

There is no standard price. Each lender sets its own extension fee in its lock policy, and the CFPB warns that extensions can be expensive. Fees are commonly quoted as a percent of the loan amount for each block of extra days. On a $400,000 loan, each 0.125% is $500, so the fee adds up fast on a long delay. Ask for the extension price in writing when you lock, before you need it.

Extensions and who pays

Who pays depends on whose delay it is. If the file sat in the lender's underwriting queue, ask the lender to cover the extension.

Some lenders will when the delay is clearly theirs.

If the delay is on your side or the transaction's (documents delivered late, seller pushed the closing date), expect to pay.

Worst case: the lock fully expires. The Federal Reserve's consumer guide is plain about what happens next: most lenders will offer the loan at prevailing market pricing. If rates rose while you were locked, you pay the higher market.

And some lenders go further: their relock policies charge the worse of your original pricing and the current market, so borrowers can't let locks lapse to chase lower rates. Ask your lender how its relock policy works.

An expired lock has no upside. Manage the calendar so you never find out.

Does rate shopping hurt your credit score?

Locking a great quote starts with having several quotes.

However, this is the part of rate shopping people needlessly fear.

Every formal mortgage application generates a hard credit inquiry, and hard inquiries can nick a credit score.

But FICO's published guidance addresses mortgage shopping directly: its scores group multiple mortgage hard inquiries made within a short shopping window into a single inquiry.

The window is 14 to 45 days depending on the score version a lender uses. Older FICO formulas use a 14-day span, the newest use 45.

Because you don't control which version gets pulled, the conservative play is simple: get all your quotes inside a tight two-week window, and the whole search counts as one inquiry under any version.

One window, one inquiry

Shopping inside one window has a second, quieter benefit: your quotes are comparable.

Rate-and-points offers gathered three weeks apart reflect three different markets, and the real gap between lenders gets lost in the market's drift.

Same week, same day if you can.

That's how we quote files as a lender: the same file, priced across the loan programs we offer at the same moment, so the comparison means something before anything gets locked.

For Southern Nevada shoppers, our conventional site follows how conventional rates are trending in Las Vegas, useful context while you build that window.

New construction: the extended lock

Standard locks assume a closing date measured in weeks.

A house that doesn't exist yet closes in months. Builder delays are common enough that the Federal Reserve's consumer guide specifically flags "unanticipated construction delays" as a reason locks die.

Lenders bridge the gap with extended lock programs for new construction: lock periods that some lenders offer for many months (illustratively 6 to 12), typically with three moving parts.

How extended locks are priced

An upfront lock deposit (illustratively a fraction of a point to a point of the loan amount, varying by lender and length), often credited back at closing if you close with that lender. Higher pricing than a standard 30- or 45-day lock: you're buying months of protection, and months usually cost more than weeks.

And, very often, a built-in float-down exercisable near closing, because no builder-buyer wants to watch the market fall for eight months while stuck with a February rate.

If your builder's timeline stretches past 60 days, ask for the extended-lock terms and read the float-down rules before you pay the deposit. The details (trigger, cutoff, one-time use) do all the work.

Mortgage rate lock FAQ

The bottom line

A mortgage rate lock gives you a fixed rate and points for a set period you choose.

Its price can be small next to what a quarter-point float against you costs: about $66 a month on a hypothetical $400,000 30-year fixed loan, principal and interest only, for thirty years.

Lock when the payment works and the period covers your closing date with cushion.

Float only with real budget slack and no illusions about forecasting.

Pay for a float-down when the lock is long or the market is jumpy.

If closing slips, compare the extension fee with the cost of relocking before you let a lock lapse.

Finally, do all your shopping inside one tight window so your credit score barely notices.

Bring us your timeline. We'll compare lock options across the loan programs we offer and give you a plan, not a prediction.

Updated October 18, 2026: added a lock period planner, a lock-or-float comparison and an answer on extension costs.