Mortgage rates move every day, and sometimes several times a day. Between the time you apply and the time you close, a small change in rates can raise or lower your monthly payment by a meaningful amount. A mortgage rate lock protects you from that movement by fixing your rate for a set period. This guide explains how locks work, what they cost, and how to choose the right moment and length.
What a rate lock is
A rate lock is a lender’s commitment to honor a specific interest rate and number of discount points for a specific period, as long as your loan closes on time and your application does not change in ways that affect pricing. If market rates rise during the lock, your rate stays the same. If they fall, you generally keep the higher locked rate unless your lock includes a float-down provision.
The lock covers the rate and points for the particular loan program, loan amount, and property described in your application. It is usually confirmed in writing, and the Loan Estimate you receive will show whether your rate is locked and when the lock expires.
When you can lock
Most lenders let you lock once you have a signed purchase contract and have submitted a full application. Some allow you to lock earlier, during preapproval, through special programs. Refinance borrowers can typically lock as soon as the application is in process.
Lock periods
Common lock periods are 30, 45, and 60 days. Some lenders offer 15-day locks for loans that are nearly ready to close and longer locks of 90 days or more for new construction. In general, longer locks carry a higher cost because the lender bears more risk that rates will move.
Choose a lock period that comfortably covers the time needed to close. Consider:
- The closing date in your purchase contract.
- How quickly the lender is processing files.
- Whether an appraisal, inspection, or title issue could cause delays.
- Holidays and weekends near the closing date.
What a lock costs
Many lenders include a standard lock of 30 to 60 days in their pricing at no separate fee. The cost is built into the rate. Longer locks may be priced with a slightly higher rate or an upfront fee, sometimes a fraction of a percent of the loan amount, which may or may not be credited at closing. Ask your loan officer:
- Is there a lock fee, and is it refundable?
- How does the rate differ between a 30-day and a 60-day lock?
- What does an extension cost?
Lock extensions
If closing is delayed past the expiration date, you will need an extension or a relock. Extension fees are commonly charged per day or for blocks of days, and they can be expressed as a percentage of the loan amount. If the delay was caused by the lender, ask the lender to cover the cost. If the lock expires without an extension, the lender may reprice the loan at the current market rate or at the worse of the original and current rates, depending on its policy.
Float-down options
A float-down lets you capture a lower rate if market rates fall after you lock. Policies vary widely. Some lenders offer it free, others charge an upfront fee, and most require rates to drop by a minimum amount, such as a quarter of a percentage point, before you can use it. You may be allowed to exercise it only once and only within a certain window before closing. Read the terms carefully and compare the cost with the likelihood of a meaningful drop.
What can change a locked rate
A lock is not absolute. Your rate or pricing can change if:
- Your credit score changes after a new credit pull, for example because you opened a new card or missed a payment.
- The appraisal comes in low, changing your loan-to-value ratio and potentially the pricing tier or mortgage insurance.
- Your loan amount or down payment changes.
- Your income or employment can’t be verified as stated.
- You change loan programs, such as from a 30-year fixed to a 15-year fixed or an adjustable-rate mortgage.
- The property type or occupancy changes, for instance from primary residence to investment property.
Keep your finances stable between application and closing. Avoid new credit, large unexplained deposits, and job changes if possible.
When to lock
No one can reliably predict short-term rate movements. Trying to time the bottom can backfire if rates jump. A practical approach:
- Know your budget. Calculate the highest payment you can comfortably afford. If today’s rate fits your budget, locking removes uncertainty.
- Watch the timeline. Lock when you have a firm closing date and enough time for the lender to complete underwriting.
- Understand the market backdrop. Mortgage rates tend to follow longer-term Treasury yields and are influenced by inflation data, Federal Reserve policy, and economic reports. Big data releases can move rates quickly.
- Consider a float-down if you want protection but believe rates may fall.
The payment impact
To see why locking matters, consider a $400,000 30-year fixed loan. At 6.5%, principal and interest come to about $2,528 per month. At 7.0%, the payment is about $2,661. That difference of about $133 per month adds up to roughly $48,000 over the full term. A quarter-point move would change the payment by roughly $65 per month in this example.
Rate locks and discount points
When you lock, you lock both the rate and the pricing, which may include discount points. Paying points lowers the rate, while lender credits raise the rate in exchange for help with closing costs. The Loan Estimate shows points under Origination Charges. If you change your mind about buying points after locking, the lender will reprice according to its rate sheet.
Comparing lenders
Rate quotes are only comparable when they assume the same lock period, the same points, and the same loan details. When you shop, ask each lender for a Loan Estimate on the same day for the same scenario. Under federal rules, the Loan Estimate must be provided within three business days of your application, and your rate is not considered locked unless the form says so.
Protecting yourself
- Get the lock confirmation in writing with the rate, points, lock date, and expiration date.
- Put the expiration date on your calendar and check in with the loan officer weekly.
- Respond quickly to document requests to avoid delays.
- Ask how the lender handles a lock that expires because of an appraisal or title delay.
Lock-and-shop programs and early locks
Some lenders offer programs that let you lock a rate before you have found a home. These lock-and-shop or extended-lock programs can protect a buyer during a long search in a rising-rate environment, but they usually require an upfront fee and may carry a slightly higher rate. Read the terms on refunds, the maximum lock length, and whether a float-down is included before paying.
New construction buyers face a similar challenge because closing may be months away. Builders sometimes partner with affiliated lenders that offer long-term locks or rate buydowns as incentives. Compare that package against an outside lender, and remember that federal law allows you to choose your own lender even if the builder recommends one, although incentives may be tied to using the affiliate.
Rate locks on refinances
When refinancing, a lock works the same way, but the timeline is often driven by the appraisal and the payoff from your current servicer rather than a purchase contract. Because there is no seller deadline, it can be tempting to wait for lower rates. Decide in advance what rate makes the refinance worthwhile, based on your closing costs and how long you plan to stay, and lock when the market reaches that level.
Related reading: How a HELOC Works: Draw Periods, Variable Rates, and Smart Ways to Use Home Equity and Debt-to-Income Ratio: How Lenders Measure It and How to Improve Yours Before Applying.
Frequently Asked Questions
How long does a mortgage rate lock last?
Typically 30, 45, or 60 days, though shorter and longer periods are available. Longer locks usually cost more.
Does it cost money to lock a mortgage rate?
Standard locks are often included in the quoted pricing. Longer locks, extensions, and float-down options may carry fees or a slightly higher rate.
Can my rate change after I lock?
Yes, if your application changes, such as your credit score, loan amount, appraised value, income, or loan program. Market movements alone should not change a valid lock.
What happens if my rate lock expires?
You will need to pay for an extension or relock, which may be at the current market rate or the worse of the old and new rates, depending on the lender.
What is a float-down option?
A provision that lets you take a lower rate if market rates fall by a set amount after you lock, often for a fee and usually only once.
This article is for general informational purposes only and is not legal, medical, tax, or financial advice. Rules vary by state and change over time; confirm details with the relevant agency or a licensed professional.
