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

You found a home. Your offer was accepted. Your loan officer sends you a rate quote and asks a question most first-time buyers are not quite prepared for: do you want to lock?

That question has real consequences either way. Lock too early and you might miss a rate improvement before closing. Lock too late and you might watch the rate you were quoted climb before you get to the closing table. Float the whole way through and you are taking a risk that may or may not pay off.

This post explains exactly what a rate lock is, how long it lasts, what it costs, what your options are if rates drop after you lock, and how to think through the timing decision in Washington's current rate environment.

A mortgage rate lock is a contractual agreement between you and your lender that holds a specific interest rate for a designated period, typically ranging from 30 to 90 days. When you lock your rate, the lender commits to honoring that rate at closing, regardless of broader market movements, as long as your loan application details remain unchanged and you close within the lock period.

A rate quote is not a rate lock. Until you formally lock, the rate you were shown is just a number that reflects what the market is doing at that moment. It can move up or down tomorrow, next week, or on the day before your closing. Once you lock, that number is yours for the duration of the lock period.

A single data release, such as a jobs report, inflation data, or a Federal Reserve decision, can shift rates by 0.125% to 0.375% in one day. On a $500,000 Washington loan, a 0.375% rate move is roughly $115 per month. That is not abstract. That is the dollar cost of being unprotected during a volatile week in the bond market.

Locking your mortgage rate means securing the interest rate offered by your lender for a specific period, typically 30, 45, or 60 days. During this period, your rate won't change, even if market rates rise.

The lock period you choose should align with your expected closing date with some cushion built in. A standard purchase in Washington closes in 30 to 45 days from mutual acceptance. A 30-day lock fits that window for a straightforward conventional transaction. A 45-day lock gives you protection against the most common delays: an appraisal that takes longer than expected, an underwriting condition that needs documentation, or a title issue that surfaces mid-process.

For VA purchases, 45 days is usually the safer choice. VA appraisals can add time to the closing process, and unexpected delays from inspections, title issues, or underwriting conditions are common. The extra protection is usually free or costs very little compared to the risk of an expired lock.

FHA and 203(k) renovation loans carry longer closing timelines than standard conventional loans. If you are financing a construction loan or a rehab product, your loan officer should help you choose a lock period that reflects the actual timeline for your specific loan type, not the average for a simple purchase.

Most locks are free for standard periods of 30 days. Longer locks, float-down options, and extensions carry additional costs that vary by lender. 

A 45-day lock is often free or minimally priced at most lenders. A 60-day lock typically carries a small cost, sometimes expressed as a fraction of a point, meaning a percentage of the loan amount. On a $500,000 loan, a 0.125-point lock extension fee is $625. That is the price of an extra 15 to 30 days of rate protection.

Some lenders charge a specific rate lock fee, while others lock your rate for free. However, even free locks often have the cost baked into the mortgage rate itself. A loan with a 60-day lock might have a slightly higher interest rate than a loan with a 30-day lock.

The important thing to understand is that all lock costs are real, whether they appear as a direct fee or as a slight rate adjustment. Your loan officer should show you the tradeoff clearly so you can decide whether the longer protection period is worth the cost for your timeline and risk tolerance.

If you do not close before your rate lock expires, you lose the locked rate. Never assume a lock will be automatically extended. Most lenders require a formal extension request before the lock expires, not after. If you miss the expiration date without requesting an extension, you lose the locked rate entirely and must re-lock at whatever the market offers.

Extensions are available but they cost money. The cost is typically based on how many additional days you need and the current rate environment. If rates have risen since you originally locked, the extension fee may be meaningful. If rates have fallen, your loan officer can sometimes cancel the original lock and re-lock at the lower rate, a process that requires lender approval and a day or two to process.

Your loan officer should be monitoring your lock expiration proactively and alerting you with enough lead time to request an extension without scrambling. If that communication is not happening, ask.

A float-down option addresses the most common anxiety buyers have about rate locks: what if I lock today and rates drop tomorrow?

A float-down option allows borrowers with a mortgage rate lock to reduce their interest rate if market rates fall. It provides an exception to a rate lock and reduces your rate if market rates go down during the lock period.

The mechanics vary by lender. Float-down options require the offered rate to decrease by a minimum amount before the buyer can exercise the option. For example, a lender may say rates must drop by 0.5% before you can trigger the float-down. If your locked rate is 6.5% and rates drop to 6.25%, the option cannot be used because the drop is only 0.25%.

Most lenders charge a fee for a float-down option, often in the range of 0.25% to 1% of the loan amount. On a $350,000 loan, that could cost between $875 and $3,500.

The float-down is worth exploring when rates are actively declining and you want protection in both directions. It is less valuable when rates are stable or rising. Ask your loan officer whether it is available and what the specific trigger and cost are before you decide.

LINK: "How the current Washington rate environment affects your lock decision"

Floating means you delay locking and accept whatever rate is available when you eventually commit. It is a bet that rates will improve before your closing date.

Locking makes sense when rates are stable or rising, your budget is tight and a rate increase of even 0.25% would affect your qualifying DTI or payment comfort zone, or when the news cycle is volatile with Fed meetings, employment data releases, or geopolitical events that can swing rates sharply in a single day.

Floating makes sense only when you have time, clear downward rate momentum, and room in your budget to absorb a move higher. If rates have been dropping consistently for several weeks and economic data suggests the trend will continue, floating can capture a lower rate than what is available today. 

In Washington's spring 2026 market, rates have been volatile. They touched sub-6% briefly in February before climbing back toward 6.3% to 6.5% range as geopolitical uncertainty returned. That pattern, where rates dip and then snap back, is exactly the environment where locking at the right moment matters and floating can cost you.

If you have an accepted offer and a closing date within 30 to 60 days, locking is almost always the right move. The upside of floating is marginal if your closing is imminent. The downside of a rate spike during that window is real and immediate. Sammamish Mortgage

A rate lock is tied to the specific details of your loan application. If you switch loan types, change your down payment amount, or your credit score takes a significant dip, your lender may void the rate lock and recalculate your rate based on the new information.

This is why the period between offer acceptance and closing is not the time to open new credit accounts, change jobs, make large purchases, or shift your down payment amount. Any material change to your financial picture can unravel a lock you thought was protecting you.

Your rate is locked to the file as it exists when you lock it. Keep the file stable until closing.

LINK: "What to protect during the 30 to 45 days between offer and closing"

A rate lock is not a complicated decision. It is a risk management tool, and like all risk management, the right answer depends on your specific timeline, your budget tolerance, and what the market is doing at the moment you are ready to commit.

For most buyers in Washington who are under contract with a closing date in sight, locking promptly after mutual acceptance removes a variable you cannot control. The market will do what it does. Your locked rate will not move.

If you want optionality in a falling rate environment, ask about a float-down option before you lock. Know what it costs and what triggers it. Then decide whether the insurance is worth the premium for your situation.

Have questions about when to lock your rate or whether a float-down option makes sense for your transaction?

Schedule a free 15-minute call and we will walk through the current rate environment, your closing timeline, and the right lock strategy for your specific loan before you commit.

Or call or text directly: (360) 801-6980

Terry Leinneweber | NMLS #2003490 | Dwell Mortgage | Licensed in Washington State