Reviewed by Jeff Shin, NMLS #1041652. Updated .
Also called: mortgage rate lock, lock-in.
How long a lock lasts
The CFPB notes that locks commonly run 30, 45, or 60 days, and longer locks may be available. A longer lock usually costs more, in a slightly higher rate or a fee. Pick a lock period that covers your closing date with some room to spare.
What can still change a locked rate
A lock holds the price for the loan you applied for. Per the CFPB, if your application changes, the lender may change the rate. Changes that can do it include the loan type, the down payment, the appraised value, your credit score, or your documented income.
If closing runs late
If the lock expires before you close, you may have to pay to extend it, and the CFPB warns that extensions can be expensive. The Loan Estimate does not show extension costs, so ask about them before you lock. See rate lock extension checks.
Locking vs. floating
If rates fall after you lock, you may not get the lower rate. Some lenders offer a float-down option, usually for a cost. Floating keeps that chance open but leaves you exposed if rates rise. Read locked vs. floating rate quotes.
Related terms
Related on BankPricer
Sources
Definitions on this page are summarized from the agencies that set the rules. Lenders can add stricter requirements. Checked October 7, 2026.
Not sure which of these applies to you?
That is usually the actual question. Send the situation rather than the product name — purchase or refinance, primary or investment, price range, and timeline — and you get the structures that fit, with what each one costs.