You found the home, your offer was accepted and your lender quoted a rate you are happy with. Then comes the waiting: the appraisal, the underwriting, the title work and the paperwork, often 30 to 45 days before you close. During that time mortgage rates keep moving, sometimes by a quarter point or more in a single week. A rate lock is the tool that protects you from that movement. Used well, it can save you thousands. Used carelessly, it can cost you fees or leave you stuck at a worse rate.
A rate lock is a lender's commitment to hold a specific interest rate and set of points for you for a defined period, as long as your application details do not change. If market rates rise during the lock, your rate stays where it is. If rates fall, a standard lock usually keeps you at the higher locked rate, unless you have negotiated a float-down option. The lock is normally confirmed in writing and shown on your loan estimate along with its expiration date.
Lock periods and what they cost
Common lock periods are 30, 45 and 60 days, and some lenders offer 90 days or longer for new construction. Shorter locks are cheaper because the lender takes less risk. Many lenders include a 30 to 45 day lock at no extra cost and then charge for longer periods, either as an upfront fee or as a slightly higher rate, often around 0.125% to 0.25% of the loan amount for each extra 15 days. Choose a lock that comfortably covers your expected closing date plus a buffer of about a week.
Timing is the hardest part. Locking too early means paying for a long lock or risking expiration if closing slips. Locking too late leaves you exposed if rates jump. For most borrowers the best moment is once you have a signed purchase contract and a realistic closing date, and once your lender confirms your application is complete. Trying to time the market for a tiny improvement rarely pays off. Even professional traders cannot reliably predict daily rate moves.
Float-downs and extensions
A float-down option lets you take a lower rate if market rates fall by a set amount, often a quarter to half a point, before you close. It usually costs extra, either upfront or built into the rate, and each lender has its own rules about when you can use it. A float-down can be worthwhile when rates are volatile or falling, but compare its cost with the realistic chance of a meaningful drop.
If your lock expires before closing, you will need an extension, which often costs a fraction of a point for each extra week, or you may have to relock at current market rates, whichever is higher. The most common causes of delay are slow document returns, appraisal problems and title issues. Respond to lender requests within a day, order inspections early and ask your loan officer for a closing checklist so you are never the reason the clock runs out.
What can break a lock
A lock covers the loan as described in your application. If something material changes, such as your credit score dropping, your income changing, the appraisal coming in low or you switching loan programs, the lender can reprice your loan. Avoid opening new credit cards, financing furniture or changing jobs between application and closing, and tell your loan officer right away if anything changes.
A rate lock is one of the few things in the home-buying process that is fully within your control. Ask every lender for its lock periods, fees, extension costs and float-down terms in writing, and compare them alongside the rate itself. The advisors at Equity Wave Loan compare lock terms across more than 30 lenders and track your closing timeline so your rate stays protected until the keys are in your hand.