Mortgage Rate Locks on New Construction, Explained

A rate lock holds your interest rate between your loan offer and closing, as long as you close in time and your application doesn't change. On new construction, the build schedule decides how long a lock you need, so plan the lock around a realistic closing date.

What a rate lock does

The CFPB defines it simply: a rate lock means your interest rate won't change between the offer and closing, as long as you close within the lock period and nothing changes on your application.

Without a lock, your rate can move up or down at any time until you close.

How soon can I lock in a new mortgage rate?

Usually once you have a property under contract and a loan application in. The CFPB says locks are typically available for 30, 45 or 60 days, and sometimes longer.

On a home that's already built, a standard lock often covers you. On a home still under construction, it might not. The Census Bureau's data shows homes built for sale took about 7.4 months from permit to completion in 2025. You don't want a 45-day lock on a home that closes in five months.

Lenders handle this a few ways, depending on their programs:

• Lock later. Wait until the closing date is close enough for a standard lock.
• Extended lock. Lock early for a longer period, often at a cost.
• Builder or lender programs. Some offer longer locks for homes under construction.

Ask your lender which options they offer and what each costs.

At what point is a mortgage rate locked in?

When the lender confirms the lock, ideally in writing. Your Loan Estimate shows whether your rate is locked and when the lock expires.

Even after you lock, the CFPB says your rate can still change if:

• You change your loan type or down payment
• The appraisal comes in higher or lower than expected
• Your credit score changes
• The lender can't document overtime, bonus or other income

On new construction, keep your finances steady for the whole build. No new car loans, no new credit cards, no financed furniture until after closing.

How much does it cost to lock your rate?

It varies. Many lenders include standard lock periods in their pricing. Longer locks and extensions can cost more. The CFPB warns that extending a lock can be expensive if you need more time.

The Loan Estimate shows whether you're locked and for how long. It doesn't show the cost to extend or what other lock lengths would cost, so ask.

Can you get a lower interest rate on a new build?

Not because it's new. The rate depends on the market, your credit, your loan type and your down payment.

What new construction sometimes offers is a builder incentive aimed at your rate, like a temporary or permanent buydown. That's money toward lowering your rate or payment, not a different market rate. Compare it with other lenders' offers before you decide.

Questions to ask before you lock

The CFPB suggests these, and I'd add the last two for new construction:

1. What does it mean if I lock my rate today?
2. What lock period does this Loan Estimate give me?
3. Is a shorter or longer lock available, and at what cost?
4. What happens if my closing is delayed and the lock expires?
5. Under what conditions could my rate still change?
6. If I lock and rates fall, what happens?
7. When does the builder expect this home to close, and how firm is that date?
8. Do you offer a lock designed for homes under construction?

Who's writing this. I sell new homes for D.R. Horton at Collins Ridge in Hillsborough, so I represent the builder, not you. This guide is general education from my years on job sites and in sales. It isn't legal, tax or lending advice, and it doesn't describe any specific home, price or incentive. Check the sources linked below, and talk with your own lender, agent or attorney before you decide.