Until you lock, your rate floats. The Consumer Financial Protection Bureau notes that mortgage interest rates can change daily, sometimes hourly, so the rate you were quoted last week may not be the rate available today. A lock stops that movement for your loan: the rate in your offer stays your rate through closing, provided you close inside the lock window and nothing in your application changes. For buyers in Fairfax, that certainty is what lets you budget the payment with confidence instead of watching the market every morning.
When should you lock? There is no day anyone can promise is the lowest, and the CFPB frames the choice around time and cost, not prediction. Most buyers lock once they are under contract, know their closing date, and are comfortable with the payment at that rate. Choose a lock period that covers your scheduled closing with room for a delay, because a longer lock can cost more and a lock that runs short can be expensive to extend. Around Ashburn, where a standard purchase closing often leaves little spare time, buyers usually talk through the 30, 45, and 60 day options with their lender right after ratification.
A locked rate can still change, and the reasons are specific. The CFPB lists the common ones: you change the kind of loan you want or the size of your down payment, the appraisal comes in higher or lower than expected, your credit score changes because you took out a new loan or missed a payment, or your lender cannot document overtime, bonus, or other income you claimed. In Reston, the practical rule is simple: once you lock, keep your finances steady, avoid new credit, and send documents promptly so the file your lender locked is the file that closes.
You can confirm a lock in writing. Some lenders lock your rate as part of issuing a Loan Estimate, and some do not, so check the top of page 1 of your Loan Estimate to see whether your rate is locked and for how long, per the CFPB. Before you lock, ask three questions the CFPB suggests: what does it mean if I lock my rate today, what rate lock time frame does this Loan Estimate provide, and is a shorter or longer rate lock available, and at what cost? Ask also what an extension would cost if closing slips, and whether the lender offers any option if rates fall after you lock, because a lock can also lock you out of a lower rate.
FAQ
How long does a mortgage rate lock last?
Rate locks are typically available for 30, 45, or 60 days, and sometimes longer, per the Consumer Financial Protection Bureau. The right length is the one that covers your scheduled closing with room for a delay. Longer locks and extensions can cost more, so ask your lender to price the options before you choose.
How do I know if my rate is actually locked?
Check the top of page 1 of your Loan Estimate. Some lenders lock your rate as part of issuing a Loan Estimate, and some do not, per the CFPB. The form shows whether your rate is locked and for how long. If it says you are not locked, your rate can change at any time.
Can my interest rate change even after I lock?
Yes, if your application changes. Common reasons from the CFPB include changing your loan type or down payment, an appraisal that comes in higher or lower than expected, a change in your credit score, or income your lender cannot document, such as overtime or bonus pay.
What happens if rates fall after I lock, or my lock expires?
A lock holds your rate in both directions, so it can lock you out of a lower rate if rates fall after your offer, per the CFPB. If your lock expires before closing, extending it may be expensive. Ask your lender about extension costs and whether any option exists if rates fall after you lock, before you commit.