When Your Mortgage Rate Lock Is in Effect

A mortgage rate lock is in effect only once your lender has confirmed it in writing, with a locked rate, the points tied to it, and an exact expiration date and time. A rate your loan officer quoted on the phone, or one you saw in an app, is not a lock. Until the confirmation exists, your rate is floating, which means it can still change.

This matters more than usual right now. Freddie Mac's Primary Mortgage Market Survey put the 30-year fixed average at 7.28% as of October 1, 2026, up from 7.03% the week before and from 6.71% on September 3. If you are under contract and assumed you were locked when you were only quoted, the difference shows up in your payment.

The order runs like this. You complete an application. You or your loan officer ask to lock. The lender confirms the lock, and that confirmation is what starts the clock. The guide published by lender AmeriSave puts it plainly: the lock period begins when the lender formally confirms it, not when you first receive a quote.

Some locks cost money up front. PNC puts typical lock fees at 0.25% to 0.50% of the loan amount. AmeriSave says 30 to 45 day locks usually carry no upfront fee, and a 60-day lock runs about 0.125%, roughly $500 on a $400,000 loan. Pricing depends on your lender, so ask.

Then federal rules take over. If you lock after you have already received a Loan Estimate (the three-page cost disclosure lenders must send within three business days of your application), the lender has to send a revised Loan Estimate within three business days of the lock. That is required under the CFPB's Regulation Z commentary even if nothing else on the estimate changed. A revised estimate showing the lock is your paper proof.

First, the top of page 1 of the Loan Estimate. Under 12 CFR § 1026.37(a)(13), a locked loan must show when the lock ends, down to the date, time and time zone. An unlocked loan must say that the rate, points and lender credits may change until the rate is locked. If your estimate carries that second statement, you are floating, whatever you were told.

Second, the lender's own lock confirmation, which lists the fields in the checklist above. AmeriSave's advice is to save it and read it right away for errors.

Third, a place you will not find it: the Closing Disclosure. The lock terms printed on the Loan Estimate do not have to be repeated there, as compliance trainer Compliance Cohort notes. Keep the Loan Estimate and the confirmation, because they are the documents that record the deal.

The CFPB describes a lock as holding your rate only if you close within the time frame and "there are no changes to your application." It names three changes outright: loan amount, credit score and verified income.

In practice, those come from a handful of places:

• The appraisal. A low value raises your loan-to-value ratio, the share of the price you are borrowing. AmeriSave says that can add 0.25% to 0.375% to the rate.
• Your credit. AmeriSave says a 20-point score drop can trigger a 0.25% to 0.50% or larger adjustment.
• Income underwriters cannot verify. PNC says a new rate may apply if income is not satisfactorily documented. Overtime or bonus pay you counted on, but cannot document, falls into this category.
• Changing the loan itself. That covers switching from fixed to adjustable, changing the down payment, or, per NerdWallet, changing the property address.

A lock is also not approval. Underwriting can still deny a locked loan over credit, income, assets or the property.

The lock does not stretch to fit your closing date. The CFPB says you may have to pay to extend it even when the delay was the lender's fault, and the Loan Estimate does not show extension prices. AmeriSave sells extensions in 15-day increments, up to three per loan. It also says extensions must be requested before the lock expires, because an expired lock cannot be extended. If you let it lapse, the loan reprices at whatever the market is that day. The costs and the ways around them are in what a lock extension costs.

Find your Loan Estimate and read the top of page 1. If it says the rate may change until locked, you are not locked. If you locked after the first estimate, confirm that a revised one arrived within three business days.

Put the lock's expiration date and time next to your contract closing date. If the gap is a few days or less, ask your lender now what an extension costs, and request one at least a week ahead if you need it. The step from clear to close to the closing table takes time of its own, so build that into the gap.

If you only have a quote and no confirmation, your rate is still floating in a market that rose 0.57 points in September. Before you lock, it is worth seeing what other lenders would put in writing for the same loan.