Should I Lock In My Interest Rate?

Lock your rate once you have chosen a lender and, for a purchase, signed a contract with a closing date, and pick a lock period that runs past that date. A rate lock is a lender's promise to hold your interest rate and any points (upfront fees paid to lower the rate) until a set date and time, as long as you close by then and your application does not change. Rates can move quickly: Freddie Mac's weekly average for a 30-year fixed mortgage rose from 6.71% on September 3, 2026, to 7.40% on October 8, 2026. The tradeoffs are that a standard lock does not drop if rates fall, and extending a lock that runs out can cost extra.

When should you lock?

Lock with the lender you plan to close with, after you have compared Loan Estimates, the standard offer forms lenders send after you apply. A lock is one lender's promise, so it does not help if you switch lenders later. The "Rate Lock" line at the top of page 1 of the Loan Estimate shows whether your rate is locked and until when. Some lenders lock when they issue the Loan Estimate, and others wait until you say you want to proceed.

A signed purchase contract gives you the closing date you need to size the lock. The Consumer Financial Protection Bureau (CFPB), the federal agency that writes mortgage disclosure rules, says to make sure the lock covers the time until you close.

To decide whether to hold out for a lower rate, put a dollar figure on the risk. Here is what Freddie Mac's 2026 weekly averages would mean for a $350,000, 30-year fixed loan:

Floating, meaning leaving your rate unlocked, from September 3 to October 8 would have raised the payment by $162.53 a month, about $1,950 a year. Floating for three weeks in April would have lowered it by $52.58 a month. Your own quote will differ from the national average. Lock now if a rise like the fall 2026 move would push your payment past your budget, or push your debt-to-income ratio (DTI), your monthly debt payments divided by gross monthly income, above what your lender will approve.

How long does a lock last, and what does it cost?

Locks are typically available for 30, 45, or 60 days, and sometimes longer, according to the CFPB. Choose a period that covers your closing date plus time for delays. The Federal Reserve's guide to lock-ins lists common causes, such as waiting on documents from you, your employer, the appraiser, a builder, or the seller. If your lock looks too short, the CFPB suggests asking for a longer one right away.

Lock pricing varies by lender. The Federal Reserve's guide says a lock fee can be a flat fee, a percentage of the loan amount, or a fraction of a percentage point added to your rate, and that a longer lock usually costs more. Some lenders collect the fee up front and keep it if you withdraw, are denied, or do not close. Federal rules bar the lender from charging a lock fee, or any fee except a credit report fee, until you have received the Loan Estimate and said you intend to proceed. A separate lock fee appears with the other lender fees in Section A of the Loan Estimate.

The Loan Estimate does not show what a shorter or longer lock would cost, or what an extension would cost. Ask the lender for those prices before you lock.

What happens if closing is delayed past your lock?

If you do not close before the lock expires, your rate and points can change, and the CFPB warns that you may have to pay a fee to extend the lock even when the delay comes from the lender's own processing time. If a lock lapses without an extension, the Federal Reserve's guide says most lenders offer the loan at that day's rate and points, which cost more if rates have risen.

Before you lock, ask the lender:

• What does an extension cost, and how many days does it add?
• Who pays for an extension if the lender, appraiser, or another party causes the delay?
• If the lock expires, can you re-lock at that day's pricing, and is there a fee?

Get the answers in writing if your closing date is uncertain, as with a home still under construction.

How does a float-down option work?

Some lenders will lower a locked rate if their rates fall before closing, a feature often called a float-down. The Federal Reserve's guide says that once you lock, you benefit from a rate drop only if your lender is willing to lock in the lower rate, and the CFPB notes that rate lock policies vary by lender. Ask before you lock:

• Is a float-down offered, and what does it cost?
• How far must rates fall before you can use it?
• How many times can you use it, and how close to closing?

Switching to another lender to get a lower rate means starting the loan process over, which the CFPB says could delay or endanger your closing.

What should you receive after you lock?

1. Lock terms on the Loan Estimate. The "Rate Lock" line must say whether the rate is locked and, if it is, the date, time, and time zone when the lock ends.
2. A revised Loan Estimate within three business days. If your rate was not locked when you got the first Loan Estimate, federal rules require the lender to send a revised one within three business days after you lock. It shows the locked rate, points, and lender credits (money the lender puts toward your closing costs in exchange for a higher rate). A revised Loan Estimate must reach you at least four business days before closing and cannot be issued once you have the Closing Disclosure, the final cost form. When it is too late for one, the lender shows the locked terms on the Closing Disclosure instead.
3. A corrected Closing Disclosure, if you lock late. If you lock after receiving the Closing Disclosure, the lender must correct it. If the lock raises your APR (annual percentage rate, the yearly cost of the loan including interest and certain fees) by more than 1/8 of a percentage point on most loans, you must receive the corrected form at least three business days before closing, which can push back your closing date.
4. Written lock terms. The Federal Reserve's guide warns that oral lock promises are hard to prove in a dispute. Ask for a written lock agreement or confirmation that lists the rate, points, any lock fee, and the expiration date.

A lock holds the price; it is not loan approval. The Federal Reserve's guide notes that a lock is not a loan commitment, which is the lender's promise to make the loan. The CFPB says a locked rate can still change if your application changes: you switch loan types or change your down payment, the appraisal comes in higher or lower than expected, your credit score changes, or the lender cannot document overtime, bonus, or other income. The mortgage approval process covers the steps that happen while your lock runs, and how APR differs from the interest rate helps you compare a locked offer with others. For choosing the lender you lock with, see how to choose the best lender for your mortgage.