What Is a Mortgage Rate Lock and When Should You Use

What Is a Mortgage Rate Lock and When Should You Use One?

You found the house. You got approved. The rate looks good. Then someone asks: "Did you lock your rate?"

If you don't know what that means, you're not alone. A mortgage rate lock is one of the most important decisions you'll make during the home buying process, and most buyers barely understand it. Let's fix that.

What a Rate Lock Actually Does

A rate lock is a guarantee from your lender that your interest rate won't change for a specific period of time, usually 30 to 60 days. Once you lock, it doesn't matter if rates spike the next day. Your rate is frozen.

Without a lock, your rate "floats." That means it moves with the market every single day until you close. Some days it might drop. Other days it might jump a quarter point, which on a $400,000 loan adds roughly $60 to your monthly payment. For 30 years.

That's the core trade-off: certainty versus gamble.

How Rate Locks Work

Here's the typical process:

• You apply for a mortgage and get approved
• Your loan officer quotes you a rate based on current market conditions
• You decide to lock that rate for a set period (usually 30, 45, or 60 days)
• The lender confirms the lock in writing with the rate, points, and expiration date
• You close before the lock expires, and you get that rate

Most locks are free for 30 to 45 days. Longer locks (60 or 90 days) may cost a small fee or come with a slightly higher rate, because the lender is taking on more risk by holding that rate for you.

When Should You Lock?

The short answer: lock when you have a purchase agreement and you're comfortable with the rate.

Here are the scenarios where locking makes the most sense:

Lock when rates are rising

If the Federal Reserve is signaling rate increases, or if bond yields are climbing, rates tend to follow. Locking protects you from paying more by the time you close.

Lock when you have a firm closing date

If your closing is 30 to 45 days out, a standard lock covers you perfectly. There's almost no reason to float in this situation.

Lock when your budget is tight

If a quarter-point increase would push your monthly payment past what you can comfortably afford, lock immediately. The peace of mind alone is worth it.

Consider floating when rates are falling

If rates have been trending down consistently, you might benefit from waiting a few days. But this is a gamble. Rates can reverse direction without warning.

What Happens If Rates Drop After You Lock?

This is every buyer's fear. You lock at 6.5%, and the next week rates drop to 6.25%.

Some lenders offer a "float-down" option. This lets you take advantage of a lower rate if the market drops after you lock, usually with some conditions. Not all lenders offer this, and it may come with a fee. Ask about it before you lock.

If your lender doesn't offer a float-down, you're stuck with your locked rate. But here's the thing: you locked because the rate worked for your budget. A slightly lower rate would have been nice, but you didn't lose money. You gained certainty.

What If Your Lock Expires?

If your closing gets delayed and your lock expires, you have a few options:

• Lock extension: Most lenders will extend your lock for a fee, typically 0.125% to 0.25% of the loan amount
• Re-lock at current rates: If rates have gone up, this hurts. If they've gone down, it might actually help
• Negotiate: If the delay was the lender's fault, they may extend for free

The best way to avoid this problem is to choose a lock period that gives you a comfortable buffer beyond your expected closing date.

Common Rate Lock Mistakes

Locking too early. If you lock before you have a signed purchase agreement, you're burning lock time during the house hunt. Most lenders won't lock until you have a contract anyway.

Choosing too short a lock. A 30-day lock is cheaper, but if anything delays your closing (appraisal issues, title problems, inspection negotiations), you'll need an expensive extension.

Not getting it in writing. A verbal rate quote is not a lock. Get written confirmation with the rate, points, lock date, and expiration date.

Ignoring the fine print. Some locks have conditions. If your credit score drops, your loan amount changes, or your property appraises differently, the lender may adjust or void the lock.

Rate Lock Timing in 2026

In the current market, rates have been volatile. Weekly swings of 0.125% to 0.25% are common. That kind of movement can add or subtract tens of thousands of dollars over the life of a loan.

For most buyers in 2026, the smart play is to lock once you have a purchase agreement and a rate you can live with. Trying to time the absolute bottom is a fool's errand. Even mortgage industry veterans can't predict rate movements with any consistency.

The Bottom Line

A rate lock removes one of the biggest variables from your home purchase. You know exactly what your payment will be, and you can plan accordingly. In a volatile rate environment, that certainty is worth its weight in gold.

Don't overthink it. If the rate works for your budget, lock it and move forward.

Want to see what rate you'd qualify for today? SOMA can walk you through your options in minutes, with no commitment and no pressure.