Mortgage Rate Lock Explained: How It Works and What It Costs
A mortgage rate lock is a lender's agreement to hold a specific interest rate for a set period of time while your loan moves through underwriting and toward closing.
Official Source: Consumer Financial Protection Bureau (CFPB) — "What's a Lock-In or a Rate Lock on a Mortgage?" — https://www.consumerfinance.gov/ask-cfpb/whats-a-lock-in-or-a-rate-lock-en-143/
According to the CFPB, mortgage interest rates can change daily, sometimes hourly. If your rate is locked, it won't change between the lock date and closing, as long as you close within the specified time frame and nothing material changes in your application. This guide explains how rate locks work, what they typically cost, and what to ask your lender before agreeing to one.
Table of Contents
- Definition
- How a Rate Lock Works
- Typical Lock Periods
- What Can Still Change a Locked Rate
- The Float-Down Option
- Rate Lock Extension Costs
- Step-by-Step: Deciding When to Lock
- A Real-World Example
- Common Mistakes
- Expert Tips
- Related Calculators
- Frequently Asked Questions
- References
- Conclusion
Definition
A mortgage rate lock is a written agreement between a borrower and lender to hold a specific interest rate, and often the associated points, for a defined period while the loan is processed and moves toward closing.
How a Rate Lock Works
Without a lock, your quoted rate is "floating," meaning it can move up or down with market conditions at any time before closing. Once you lock, the lender commits to honoring that rate as long as your loan closes within the agreed timeframe and your application details don't materially change. Some lenders lock the rate automatically when issuing a Loan Estimate, while others require you to request it separately.
Typical Lock Periods
According to the CFPB, rate locks are commonly available for 30, 45, or 60 days, though shorter and longer periods may be offered depending on the lender and loan type. The right lock period depends on your expected closing timeline. A purchase transaction often locks once you have a signed contract, while a refinance typically locks once the rate supports your goals.
What Can Still Change a Locked Rate
A rate lock isn't an unconditional guarantee. According to the CFPB, even a locked rate can still change if there are changes to your application, including your loan amount, credit score, or verified income. A rate lock also isn't the same as loan approval. Underwriting can still uncover issues with your credit, income, assets, or the property that affect whether the loan closes at all.
The Float-Down Option
Locking protects you if rates rise, but it can also prevent you from benefiting if rates fall afterward. A float-down option, often available for an added cost, allows you to access a lower rate if market rates drop during your lock period, subject to conditions set by the lender.
Rate Lock Extension Costs
| Situation | Typical Outcome |
|---|---|
| Loan closes within the lock period | Locked rate applies as agreed |
| Closing is delayed and the lock expires | Extension may be available, often for an added fee |
| Borrower caused the delay | Borrower is more likely to bear the extension cost |
| Lender caused the delay | Borrower can ask the lender to cover or waive the extension fee |
Your Loan Estimate will state whether your rate is locked and for how long, but it typically won't show the cost to extend the lock or the cost of choosing a different lock period. It's worth asking your lender directly for those specifics in writing.
Step-by-Step: Deciding When to Lock
- Confirm you have a realistic closing timeline before requesting a lock, since a purchase loan often locks after a signed contract.
- Choose a lock period with enough cushion to comfortably reach your expected closing date.
- Ask your lender in writing for the locked rate, points, lock expiration date, and any extension costs.
- Ask specifically whether a float-down option is available and what it costs.
- Avoid actions that could change your application, such as opening new credit, during the lock period.
- Compare your Loan Estimate and Closing Disclosure to confirm the rate matches what was locked.
A Real-World Example
A buyer locks a rate at application with a 45-day lock period, expecting to close within that window. A delay in the seller's paperwork pushes the closing date past the lock's expiration. Because the delay wasn't caused by the buyer, they ask the lender whether the extension fee can be waived. The lender agrees to extend the lock at no additional cost, since the delay originated with a third party rather than the borrower.
Common Mistakes
- Assuming a locked rate is completely guaranteed regardless of changes to the loan application.
- Not asking about extension costs before choosing a lock period that's too short for a realistic closing timeline.
- Opening new credit accounts during the lock period, which can affect the application and void the locked terms.
- Assuming a rate lock also guarantees loan approval, rather than just the interest rate.
- Not asking about a float-down option if there's a reasonable chance rates could fall before closing.
Expert Tips
- Ask your lender to put the locked rate, points, lock period, and extension costs in writing before proceeding.
- Choose a lock period with a comfortable buffer beyond your expected closing date.
- Avoid financial changes, like new credit accounts or job changes, during the lock period.
- Ask specifically who bears the cost of an extension if the closing is delayed by the lender or another third party.
Related Calculators
Related Articles
- APR vs. Interest Rate: What's the Difference?
- What Are Mortgage Discount Points and Should You Buy Them?
Frequently Asked Questions
Does a rate lock guarantee my loan will be approved?
No. A rate lock only guarantees the interest rate, not loan approval. Underwriting can still identify issues with credit, income, assets, or the property that affect approval.
Can my locked rate still change?
Yes, in certain situations. If your loan amount, credit score, or verified income changes during underwriting, your locked rate can be affected even if you have a lock agreement.
What is a float-down option?
A float-down option lets you access a lower rate if market rates drop during your lock period, though it typically comes with an added cost and specific conditions set by the lender.
Who pays if my rate lock expires before closing?
It depends on why the delay happened. If the borrower caused the delay, they're more likely to bear the extension cost. If the lender or a third party caused it, the borrower can ask for the fee to be waived or covered.
References
- Consumer Financial Protection Bureau – What's a Lock-In or a Rate Lock on a Mortgage?
- Consumer Financial Protection Bureau – Content of Disclosures for Certain Mortgage Transactions (Regulation Z, Rate Lock)
- Federal Reserve – A Consumer's Guide to Mortgage Lock-Ins
Conclusion
A mortgage rate lock provides valuable protection against rising rates while your loan moves toward closing, but it comes with conditions worth understanding upfront, including what can still change your rate and what an extension might cost if your closing is delayed. Getting the lock terms in writing and asking about float-down options are simple steps that can save real money. This article is educational only and not financial advice; rate lock terms, costs, and float-down availability vary by lender, so confirm specifics with your mortgage lender before locking.