Rates & costs
Mortgage rate locks: when to lock, how long, and what it costs
Quick answer
A rate lock is a lender's promise to hold your interest rate and points for a set period, usually 30 to 60 days, while your loan closes. Short locks are often free; longer locks cost more. If closing slips past the lock date, you pay an extension fee or take the current market rate. Most buyers lock once they have an accepted offer.
Mortgage rates change every day, sometimes several times a day. A rate lock protects you from that movement between application and closing. Timing it well, and choosing the right length, can save thousands — and getting it wrong can cost you an extension fee or a higher rate.
How a rate lock works
When you lock, the lender guarantees a specific interest rate and price (points or credits) for your loan, provided you close within the lock period and nothing material changes in your file. If rates rise during the lock, you keep your rate. If they fall, you usually keep your rate too — unless you have a float-down option.
When you can lock
Most lenders let you lock once you have a signed purchase contract and a completed application. Some offer a lock-and-shop program that locks before you find a home, usually for a fee or a slightly higher rate. When you lock after receiving your Loan Estimate, the lender must send a revised Loan Estimate within three business days showing the locked terms.
How long to lock
| Lock length | Typical use | Cost |
|---|---|---|
| 15–30 days | Refinances, fast purchases | Usually best pricing |
| 45 days | Most purchases | Small added cost, often built into rate |
| 60 days | Purchases with longer contracts | Slightly higher rate or fee |
| 90+ days | New construction | Higher cost, sometimes an upfront deposit |
Pick a lock that covers your contract's closing date plus a few days of cushion. Locking too short risks an extension; locking much too long costs you for time you don't need.
A real example
On a $400,000 loan, the difference between 6.50% and 6.75% is about $66 a month, or roughly $23,800 over 30 years. A buyer who locks at 6.50% with a signed contract is protected if rates jump to 6.75% before closing. If closing is delayed a week past the lock, an extension might cost around 0.125% of the loan ($500) — far less than losing the rate.
Extensions and relocks
If closing slips past your lock expiration, the lender can extend the lock for a fee, often charged per day or per week. If the lock expires entirely, you may have to relock at the current market rate or the worse of the old and new rates, depending on the lender's policy. Ask about this before you lock.
Float-down options
A float-down lets you take a lower rate if the market drops meaningfully after you lock. It's usually a one-time option, may carry a fee, and often requires rates to fall by a set amount, such as 0.25%. It can be worth it on long locks in a falling-rate market.
What can break a lock
- A change in loan amount, loan type or down payment
- A lower credit score at a re-pull
- A change in occupancy or property type
- A low appraisal that changes your loan-to-value ratio
Any of these can change your price even while locked, because the lock covers a specific loan scenario.
Frequently asked questions
Should I lock or float?
No one can predict short-term rate moves. If the locked payment fits your budget, locking removes the risk. Floating only makes sense if you can afford a higher rate should the market move against you.
Does locking a rate cost money?
Standard locks of 30 to 45 days are usually included in your pricing. Longer locks, extensions and float-downs typically cost extra.
Can I switch lenders after locking?
Yes, but your lock doesn't transfer. You'd start a new application and lock with the new lender, which can delay closing.
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Take the readiness assessment Take the readiness assessment →This article is educational and general in nature. Loan eligibility, rates, and requirements vary by lender, loan program, and your individual situation. Confirm specifics with a licensed lender.