How does a mortgage rate lock work, can it float down if rates improve, and how long is it valid?
A rate lock holds your interest rate for a set period, commonly 30, 45 or 60 days, so it won't rise before closing even if market rates do. It won't fall with the market either, unless your lock includes a float-down option, which some lenders offer. Longer locks and float-down options generally cost more than a basic 30-day lock.
Last updated September 29, 2026What happens when you lock a rate?
Before you lock, your rate "floats" and can move up or down each day with the market. Locking fixes it for an agreed number of days while the loan goes through underwriting to closing. It cuts both ways: if rates drop after you lock, a standard lock keeps you at the rate you locked.
Can the rate float down if rates improve after I lock?
Only if you have a float-down option, and not every lender offers one. It lets you ask, usually once, for a lower rate if the market falls enough before closing. The catch is that a lock with a float-down often starts a little higher than the same lock without one, because the option's cost is built into the rate rather than billed as a separate fee.
How long does a lock last, and what does it cost?
Lock periods commonly run 30, 45, 60, 90 or 120 days. A 30-day lock is usually the cheapest, and 45 days often fits a typical application-to-closing timeline better. Longer locks usually cost more, through a fee, a slightly higher rate or both, because the lender is holding the price longer.
Discount points are a separate choice: you pay up front to lower the rate. How much each point lowers it depends on the lender and the day's pricing, so ask for quotes with and without points.
Does shopping around hurt my credit?
Not much, if you do it in a short window. Credit scoring models count several mortgage inquiries made within a set shopping period as one, so comparing lenders doesn't mean a separate hit for each.
It depends on your situation:
- You haven't locked and think rates are falling: you can choose to keep floating, but you take the risk they rise instead.
- Your lender offers a float-down and rates drop after you lock: you may be able to get the lower rate once before closing, on that lender's terms.
- Your quote is weeks old: rates move daily, so get a current quote before you lock.
- You find a better rate elsewhere mid-process: switching lenders before closing is sometimes possible, but it can delay closing and cost you fees already paid.
| Common lock lengths | 30, 45, 60, 90 or 120 days |
|---|---|
| Cheapest lock | Usually 30 days |
| Longer locks | Usually cost more, as a fee or a higher rate |
| Float-down option | Optional, not offered everywhere, often priced into a higher starting rate |
| Rate shopping and credit | Mortgage inquiries in a short shopping window count as one |
| Old quotes | Rates change daily; get a current quote before locking |
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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
Sourced from licensed loan officers and brokers in the FreeRateUpdate network.
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.