What a rate lock is
and why the window matters
A rate lock is your lender's promise to hold a quoted interest rate for a set period, typically somewhere around 30 to 60 days. The part that catches buyers out is the clock, because a closing that slips past the end of it generally costs money.
- A rate lock is the lender's commitment to hold a quoted interest rate for a set window, which usually runs 30 to 60 days
- If the closing slips past the end of that window, extending the lock generally costs money
- Some locks carry a float-down option, letting the borrower take a lower rate once if the market improves before closing, generally for a fee or a slightly higher starting rate
Explainer. Written by The JK Realty Group.
Rates move. A number a lender quotes you on a Tuesday is not automatically the number you get at settlement, and a rate lock is what closes that gap. It is the lender's commitment to hold a quoted rate for a set window, which usually runs somewhere around 30 to 60 days. Inside the window the rate is yours regardless of what the market does. Outside it, you are back to whatever is being quoted that day.
The clock is the part buyers tend to underestimate. The window starts when you lock, not when your closing date gets settled, and a purchase has more moving pieces than most people expect. A township inspection backing up, a title question that takes time to clear, a lender condition that needs one more document: any of them can push a closing by a week or two. If that pushes you past the end of the lock, extending it generally costs money, and how it is priced varies by lender. It is rarely a large number in the context of a house, but it is a real one, and it is easier to plan for than to be surprised by.
Some locks carry a float-down option. That lets a borrower take a lower rate once if the market improves before closing, and it is not free: a float-down generally comes with a fee or a slightly higher starting rate in exchange. Whether it is worth taking depends on the loan, how long the timeline is, and what the lender charges for it, which is a conversation to have with the lender rather than a rule that applies to everybody.
The timing question is different depending on what you are buying. A resale with a closing date already agreed and a clean file is a fairly predictable calendar. A purchase with a longer runway, a build in progress or a chain of contingencies is less so, and that is where lock length gets asked about first. Your lender is the one who can tell you what windows they offer and which one fits the closing date you are actually working toward.
What to ask, and who answers it. Ask your lender what your lock window is, the date it expires, what an extension costs and how it is charged, and whether a float-down is available on your loan. Ask your agent how the closing date is being set and what tends to move it in the town you are buying in, so the calendar you are locking against is a realistic one. Nothing on this page is a rate quote or advice about a specific loan.
Our take
A quoted rate holds only once it is locked, and that lock runs on a clock. If you are buying in South Jersey, ask what your window is and what an extension costs on the day you take the rate.
Have a question about timing? Let's talk.
General information on how the process runs. What your own lock window and extension cost will be is a question for your lender. General information, not advice about any specific property. The JK Realty Group, brokered with OMNI Real Estate Professionals. Equal Housing Opportunity. See our Terms of Use for how we source and credit these posts.