Mortgage interest rates can change daily, sometimes hourly… but locking in the rate on your mortgage loan ensures that the rate won’t change between the time you make an offer and the 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. If your rate is locked, it can still change if there are changes in your application such as you deciding to change the kind of loan you are requesting or the amount of your down payment.
Your rate could also change if the home appraisal comes in different than expected, if your credit score changes, or if your lender can’t verify your income.
If you decide to lock in a rate, 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.