Short answer: a rate lock is the lender’s agreement to give you a set interest rate if you close within a set time and your application does not change. Your Loan Estimate must say whether the rate is locked and, if it is, the date and time (with time zone) the lock ends. If you lock after you got the Loan Estimate, the lender must send a revised Loan Estimate no later than three business days after you lock. A locked rate can still change if your loan or application changes, and an extension may cost money. This page covers federal law only; other rules may apply where you live. It is general information, not legal or financial advice.
What a rate lock is
The CFPB explains that with a rate lock your rate won’t change between the lock and closing, “as long as you close within the specified time frame and there are no changes to your application”, and that if your rate is not locked, it may change at any time (CFPB, reviewed May 2, 2023, read October 30, 2026; this page may be out of date). The official comments to Regulation Z say a rate is locked for a specific period if the lender has agreed to lend at a given rate, subject to the conditions in any rate lock agreement (Supplement I, comment 37(a)(13)-1, eCFR, text up to date as of October 28, 2026). Read the conditions in your own lock agreement.
Where the lock shows on the Loan Estimate
The Loan Estimate must say whether the interest rate is locked for a specific period, under the label “Rate Lock”. If it is locked, the lender must give the date and time, including the time zone, when the lock ends. The same line must say that the interest rate, any points and any lender credits may change unless the rate has been locked, and give the date and time when the estimated closing costs expire (12 CFR 1026.37(a)(13), eCFR). The CFPB says to look at the top of page 1 to see whether your rate is locked and for how long (CFPB). The closing-cost expiry is a separate date: it is about how long you have to say you want to go ahead before the lender may revise its estimates. For that 10 business day rule and the limits on cost increases, see Loan Estimate closing cost limits.
The revised Loan Estimate after you lock
If the rate was not locked when you got the Loan Estimate, the points, lender credits and other charges that depend on the rate may change. Then, “no later than three business days after the date the interest rate is locked”, the lender must give you a revised Loan Estimate with the revised interest rate, points, lender credits and any other rate-dependent charges and terms (12 CFR 1026.19(e)(3)(iv)(D), eCFR). The official comments add that once the revised Loan Estimate shows the new points and lender credits, the points and credits at closing are compared with the revised figures, not the first ones (comment 19(e)(3)(iv)(D)-1). If the rate was already locked when you got the first Loan Estimate, the points and lender credits at closing are compared with that first Loan Estimate.
For this rule a business day is a day the lender’s offices are open to the public for substantially all of its business (12 CFR 1026.2(a)(6), eCFR). As an example only, with example dates and a lender open Monday through Friday with no holiday in between:
| Step | Example date |
|---|---|
| You lock the rate | Wednesday, March 3, 2027 |
| Revised Loan Estimate due no later than (three business days) | Monday, March 8, 2027 |
| End of an example 45-day lock counted from the lock date | Saturday, April 17, 2027 |
The real end of your lock is the date and time on your Loan Estimate or lock agreement, not a count you make yourself. If you lock on or after the day the Closing Disclosure is given, the lender may not send a revised Loan Estimate; it must give a corrected Closing Disclosure instead (comment 19(e)(3)(iv)(D)-2). For the Closing Disclosure timing and what to compare, see reviewing your Closing Disclosure.
What can still change a locked rate
The CFPB says a locked rate can still change if your application changes, including your loan amount, credit score or verified income, and gives reasons such as these (CFPB):
- You changed the kind of loan or the amount of your down payment.
- The appraisal came in higher or lower than expected.
- Your credit score changed, for example after a new loan or a missed payment.
- The lender could not document overtime, bonus or other income.
If closing runs past the lock
The CFPB notes that a lock may be expensive to extend if your closing needs more time, and that a lock may keep you from a lower rate if rates fall (CFPB). The official comments say that if you ask for a rate lock extension, the lender may use revised disclosures with a new extension fee, but that fee may be no more than the extension fee it charges in its usual course of business, and it may not use the extension to raise other, unrelated charges (comment 19(e)(3)(iv)-2). The CFPB also says the Loan Estimate does not show what the lock costs, what an extension would cost, or whether a shorter or longer lock would cost more or less, so ask the lender (CFPB). Lock fees are a cost to compare between lenders, along with the rate and the points; for how points work, see discount points and break-even math.
If you think the lender did not follow these rules, you can complain at consumerfinance.gov/complaint. For your own case, ask a lawyer; you can look for legal aid through the Legal Services Corporation.
Questions to ask the lender
- What does it mean if I lock my rate today, and is there a fee for the lock?
- How long is the lock, and what date and time does it end?
- Is a shorter or longer lock available, and at what cost?
- What happens if my closing is delayed and the lock ends, and what does an extension cost?
- Under what conditions could my locked rate still change?
- If rates go down after I lock, what happens?
Checklist
- Check the “Rate Lock” line at the top of page 1 of the Loan Estimate: locked or not, and until when.
- If you lock later, expect a revised Loan Estimate within three business days.
- Keep your application steady: loan type, down payment, credit and income documents.
- Make sure the lock runs past your expected closing date, and ask what an extension costs.
- Compare lock fees along with the rate and points.
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Sources
- eCFR: 12 CFR 1026.37, Content of disclosures for certain mortgage transactions (Loan Estimate) (Regulation Z), current text up to date as of October 28, 2026
- eCFR: 12 CFR 1026.19, Certain mortgage and variable-rate transactions (Regulation Z), current text up to date as of October 28, 2026
- eCFR: 12 CFR 1026.2, Definitions and rules of construction (Regulation Z), current text up to date as of October 28, 2026
- eCFR: Supplement I to Part 1026, Official Interpretations (Regulation Z), current text up to date as of October 28, 2026
- CFPB: What’s a lock-in or a rate lock on a mortgage? (reviewed May 2, 2023)
- CFPB: Submit a complaint
- Legal Services Corporation: Find legal aid
Disclosure: Modern Lending Solutions is not a lender, loan broker or agent for any lender or loan broker, and does not make credit decisions. Any compensation we receive is paid by participating lenders, only for advertising services. This guide is general information, not financial or legal advice.