A lock-in or rate lock on a mortgage loan means that your interest rate won’t change between the offer and closing, as long as you close within the specified time frame and there are no changes to your application.

Mortgage interest rates can change daily, sometimes hourly. If your interest rate is locked, your rate won’t change between when you get the rate lock and closing, as long as you close within the specified time frame and there are no changes to your application. Rate locks are typically available for 30, 45, or 60 days, and sometimes longer. If your rate is not locked, it can change at any time.

There can be a downside to a rate lock.  It may be expensive to extend if your transaction needs more time. And, a rate lock may lock you out of a lower interest rate if rates fall after you get your loan offer.

If your rate is locked, it can still change if there are changes in your application—including your loan amount, credit score, or verified income.  

Here are some common reasons why your interest rate might change, even though it is locked:

Rate lock policies vary by lender.  To avoid surprises, ask:

If you decide to get a rate lock, you should make sure your rate lock agreement is long enough to cover the time until you close on your loan. If you are concerned that your rate lock period might be too short, ask your lender about switching to a longer rate-lock period now.

Tip: Your Loan Estimate will state whether or not your rate is locked but it will not provide you with information about how much it would cost to extend the rate lock, how much you are paying for the specific rate lock time frame, or whether you could pay more or less for a different time frame. You should ask about those details.