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Mortgage Rate Lock: When to Lock and What It Costs

By Ivan Stamenov Updated October 18, 2026

The short version

A rate lock is your lender’s promise to hold an interest rate for you while your loan is processed, as long as you close in time and your application doesn’t change.

Locking protects you if rates rise before closing. The cost is that you usually miss out if rates fall instead. Nobody can reliably predict which way rates will move next week, including us. So the real question isn’t “will rates go up?” It’s “what would happen to my budget if they did?” If a higher payment would break your budget, locking is usually the safer choice.

How a rate lock works

According to the Consumer Financial Protection Bureau (CFPB), a rate lock means 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.

Three things to know:

  • Not every Loan Estimate includes a lock. Some lenders lock your rate when they issue a Loan Estimate, and some don’t. Check the top of page 1 of your Loan Estimate to see whether your rate is locked and until when.
  • Changes can affect your lock. A locked rate can still change if your application changes. The CFPB’s examples: you change the kind of loan or the amount of your down payment; the appraisal comes in higher or lower than expected; your credit score changes (for example, because you took out a new loan or missed a payment); or your lender can’t document your overtime, bonus, or other income.
  • The lock has to last until closing. Make sure the lock period covers the time until you close. The CFPB says locks are typically available for 30, 45, or 60 days, and sometimes longer; ask what a shorter or longer lock would cost.

Why it matters right now: how fast rates move

Rates can move enough in days to change your payment. In early October 2026, Freddie Mac’s weekly average for a 30-year fixed mortgage rose from 7.28% on October 1 to 7.40% on October 8.

Here’s what that kind of move means in dollars (example rates):

  • $400,000 loan, 30-year fixed, at 6.75%: about $2,594 a month in principal and interest.
  • The same loan at 7.00%: about $2,661 a month.

A quarter-point rise costs about $67 a month, or roughly $4,000 over five years. The current national average is shown in the reference rate banner on our mortgage recast calculator.

What a rate lock can cost

Rate lock policies vary by lender. Some include a standard lock in your pricing; others charge for it, especially for longer lock periods. A lock fee is separate from discount points, which you pay at closing to lower the rate itself (see whether mortgage points are worth it). PNC’s guide to rate locks says fees of 0.25% to 0.50% of the loan amount are common when lenders charge them; on a $320,000 loan, a 0.25% fee would be $800.

The CFPB points out a gap: your Loan Estimate shows whether your rate is locked, but not how much you’re paying for that lock period, what an extension would cost, or whether a different period would cost more or less. You have to ask.

Extensions: when closing gets delayed

If your closing is delayed past the lock’s expiration date, you’ll typically need to pay to extend the lock, or your rate can reset to whatever rates are at that point, according to PNC. Delays happen for many reasons: appraisals, title issues, or paperwork. Before you lock, ask what an extension costs, in case you need one.

Float-down options: protection in both directions

A float-down option lets you take a lower rate if market rates drop after you lock. It can cost extra, and terms vary. PNC notes that some lenders require rates to fall by a certain amount before your rate can be adjusted.

A float-down is worth considering when rates are moving a lot. Compare its cost with the payment difference you’d gain if rates dropped.

When to lock: a practical framework

Since nobody can time the market, decide based on your situation:

Locking usually makes sense when:

  • You have an accepted offer and a realistic closing date
  • The payment at today’s rate fits your budget
  • A higher payment would make the home unaffordable or stretch you too thin

Waiting to lock (called “floating”) may make sense when:

  • You don’t have a property under contract yet
  • You could comfortably absorb a higher rate
  • Your lender offers a reasonably priced float-down option, which lets you lock now and still benefit if rates fall

Questions the CFPB suggests asking your lender:

  • What does it mean if I lock my rate today?
  • What rate lock time frame does this Loan Estimate provide?
  • Is a shorter or longer rate lock available, and at what cost?
  • What if my closing is delayed and the rate lock expires?
  • If I lock my rate, are there any conditions under which my rate could still change?
  • If I lock my rate, and interest rates go down, what happens?

Add one more: Do you offer a float-down, and what does it cost?

Frequently asked questions

Does a rate lock cost money?

Sometimes. Some lenders include a standard lock period in their pricing; others charge a fee, especially for longer locks. Extensions and float-down options often cost extra. Ask your lender before you lock.

What happens if my rate lock expires before closing?

You’ll usually need to pay to extend the lock, or your rate may be reset to the market rate at that point. Ask about extension costs before you lock.

If I lock and rates go down, can I get the lower rate?

Only if your lock includes a float-down option, or if your lender agrees to adjust it. Otherwise, the locked rate stays, even if rates fall.

Can my locked rate change?

Yes, if your application changes (for example, you change the kind of loan or your down payment, the appraisal comes in different than expected, your credit score changes, or your income can’t be documented), or if you don’t close before the lock expires.

Sources

Example payments are principal and interest only, using illustrative rates. Information here is general guidance, not financial advice. Rate lock policies vary by lender; confirm the details with yours.