How does a mortgage rate lock work, can it float down if rates improve, and how long is it valid?
A rate lock fixes your interest rate for a set period, commonly 30, 45, or 60 days, so your rate will not rise even if market rates go up before closing, and it will only float down to capture a rate drop if you added that optional feature to the lock. Without a float-down feature, you will not automatically benefit from lower rates after locking. Longer locks and float-down features generally cost more than a basic short-term lock.
Last updated July 22, 2026What actually happens when you lock a rate?
Before you lock, your rate "floats" with the market and can move up or down day to day, since mortgage rates change daily. Locking fixes that rate for an agreed number of days while your loan moves through underwriting to closing. The tradeoff is symmetrical: if market rates drop after you lock, a standard lock does not let you capture that improvement. You close at the rate you locked, not a lower market rate.
Can the rate float down if rates improve after I lock?
Some, not all, lenders offer a float-down option as an add-on to a standard lock. It lets you request a one-time reduction to your locked rate if market rates fall enough before closing. The catch: a float-down lock typically starts from a slightly higher base rate than a comparable lock without the feature, since the cost of the option is often built into the starting rate rather than charged as a separate fee.
How long does a lock last, and what does it cost?
Standard lock periods commonly run 30, 45, 60, 90, or 120 days. A 30-day lock is usually the shortest and lowest-cost option, while 45 days often better matches typical application-to-closing timelines. Locks in the 60- to 90-day range and beyond generally cost more, through a separate fee and/or a somewhat higher rate, since the lender holds that pricing longer. Discount points work differently: paying points upfront buys the rate down further, but each added point produces a smaller reduction, tapering off noticeably beyond roughly three or four points.
What if my rate isn't locked yet, or I want to shop or switch?
Brokers in our network work with a panel of participating lenders, so they can price your application across multiple options at once rather than a single rate sheet. Separately, credit scoring models give special treatment to mortgage rate shopping: multiple mortgage-related hard inquiries made within a defined shopping window are typically counted as one inquiry for scoring purposes, so comparing offers does not have to mean several separate score hits.
It depends on your situation
- Not locked yet and rates trending down: deliberately holding your rate open, known as floating, is a recognized strategy, not something that just happens by default.
- Lender offers a float-down and rates drop after you lock: you may be able to request the lower rate once before closing, subject to that lender's terms.
- Got a quote weeks or months ago: treat it as outdated. Rates move daily, so always compare against a current, same-day quote before locking.
- Found a better rate elsewhere mid-process: switching lenders before closing is sometimes possible, though it can affect your timeline and any costs already paid.
| Typical lock lengths | 30, 45, 60, 90, or 120 days; 30 days is usually shortest/cheapest, 45 days often matches typical closing timelines |
|---|---|
| Longer locks | Generally cost more via a separate fee and/or a higher rate |
| Float-down feature | Optional, lender-specific; often starts from a slightly higher base rate |
| Discount points | Reduce the rate further, but each added point helps less; effect tapers markedly past about 3-4 points |
| Rate-shopping credit impact | Multiple mortgage inquiries within a defined shopping window are commonly counted as one for scoring purposes |
| Rate quotes | Change daily; a quote from weeks or months ago should not be relied on |
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Sources
- https://www.chase.com/personal/mortgage/education/financing-a-home/float-down-option
- https://www.rocketmortgage.com/learn/float-down-option
- https://www.amerisave.com/glossary/float-down-option-what-it-means-for-home-buyers-in
- https://www.lower.com/mortgages/how-long-can-you-lock-a-mortgage-rate
- https://www.amerisave.com/learn/mortgage-rate-locks-in-your-complete-guide-to-timing-costs-and-protection-strategies
- https://www.consumerfinance.gov/about-us/newsroom/cfpb-finds-americans-are-paying-upfront-fees-seeking-to-lower-interest-rates-on-mortgages
- https://www.bankrate.com/mortgages/mortgage-points
- https://www.consumerfinance.gov/ask-cfpb/what-exactly-happens-when-a-mortgage-lender-checks-my-credit-en-2005
- https://www.myfico.com/credit-education/credit-reports/how-long-do-hard-inquiries-stay-on-your-credit-report
- https://www.transunion.com/blog/credit-advice/how-rate-shopping-can-impact-your-credit-score
- https://www.experian.com/blogs/ask-experian/can-you-switch-mortgage-lenders-before-closing
- https://www.rocketmortgage.com/learn/change-mortgage-lender
- https://www.eastrise.com/blog/what-is-a-mortgage-rate-lock-how-does-it-work
- https://www.apmortgage.com/blog/mortgage-interest-rates-float-vs.-lock-strategies
- https://www.lendingtree.com/home/mortgage/rates
Educational information only, not individualized financial or legal advice. Program details and rates change; verify current terms with a licensed loan officer before making a decision.