Rate Locks and Float-Downs: When to Lock a Mortgage Rate

A rate lock is not a bet that rates have reached the bottom. It is insurance against the rate you already qualified for becoming unavailable before closing.

TL;DR

• A lock freezes the pricing for a defined period as long as the loan facts do not materially change.
• The lock period should match the real closing timeline. A 30-day lock is cheaper than a 60-day lock, but only if the file can close in 30 days.
• Extensions are expensive when the delay is yours. If appraisal, title, condo review, or borrower documents run late, extension fees can erase a cheaper quote.
• Float-downs sound simple but vary heavily. Some only apply after a large market move; others reset only once and only before final approval.
• Lock timing is a risk decision. If the payment already works and closing is soon, certainty often matters more than trying to catch a slightly lower rate.

What a rate lock actually protects

A mortgage quote is a snapshot. The lender is pricing your file against the market at that moment: loan program, credit score, loan-to-value, property type, occupancy, points, and lock period. A rate lock tells the lender to hold that pricing for a set number of calendar days, commonly 30, 45, 60, or 90.

The lock protects you from market movement, not from changes in the loan itself. If your file moves from primary residence to investment property, if the appraised value changes the loan-to-value, if the credit score band changes, or if you switch from conventional to FHA, the pricing can be redone. That is not necessarily a broken lock; it is a different loan profile.

The Consumer Financial Protection Bureau's Loan Estimate rules also matter here. A lender must give you a standardized Loan Estimate after application, and the form shows whether the rate is locked, when the lock expires, and whether points are being charged.

Why the lock period changes the price

Longer locks cost more because the lender is carrying more market risk. If rates rise while your 90-day lock is open, the lender still has to honor the locked pricing if you close on time. That risk is baked into the quote.

Two offers can look different only because they use different lock periods:

| Quote | Rate | Points | Lock period | What it really means | | --- | --- | --- | --- | --- | | Lender A | 6.625% | 0.25 | 30 days | Cheaper if the file truly closes fast | | Lender B | 6.750% | 0.25 | 60 days | More breathing room for title, appraisal, and underwriting |

The better quote is not always the lower rate. If a 30-day lock expires and costs 0.125 to 0.250 points to extend, the "cheaper" quote can become more expensive than the conservative one.

When purchase borrowers usually lock

Most buyers lock after the purchase contract is signed. At that point, the property address, price, loan amount, closing date, and inspection/appraisal timeline are real. Locking earlier is possible only through specific lock-and-shop programs, and those programs usually have rules about how quickly you must find a home and close.

The best question is not "Will rates go up?" Nobody knows that with precision. The better questions are:

• Can I still qualify if the rate rises by 0.25%?
• Does my closing date leave enough room for underwriting and appraisal?
• Is the seller, title company, HOA, or condo association likely to slow the file?
• Am I comparing lenders using the same lock period and same points?

If the answer to the first question is no, waiting to lock can put the purchase at risk.

What causes lock extensions

Lock extensions happen when the loan cannot close before the expiration date. Delays can come from any part of the transaction:

• Borrower documents arrive late or contain unexplained deposits.
• The appraisal is delayed or comes in with repair conditions.
• Title finds an issue that must be cleared before closing.
• Condo review requires a questionnaire, master insurance policy, budget, or reserve documentation.
• The seller changes the closing date.
• The borrower changes loan program, down payment, or credits.

Ask the loan officer who pays for the extension under different delay scenarios. Some lenders absorb extension costs when the delay is internal. Many pass the cost through when the delay is caused by the borrower, property, seller, or third parties.

Float-downs: useful, but not magic

A float-down lets a locked borrower capture some benefit if market rates fall after the lock. The important word is some. Float-down rules vary by lender and often include restrictions:

• The market must improve by a minimum amount, such as 0.25% or 0.50%.
• The feature may be available only once.
• It may have to be requested before a certain milestone, such as final approval.
• It may reduce the rate but not the points.
• It may cost an upfront fee or require a slightly worse starting rate.

If a lender advertises a float-down, ask for the trigger, deadline, cost, and whether it applies to the exact program you are using. A float-down that requires a large market move may be more of a comfort feature than a likely savings path.

How to compare lock offers

Use the same structure for every lender:

| Item to compare | Why it matters | | --- | --- | | Rate | Sets principal and interest payment | | Points or lender credits | Shows whether the rate is bought down or subsidized | | Lock period | A 30-day quote is not the same as a 60-day quote | | Extension cost | Shows the penalty if closing slips | | Float-down terms | Shows whether lower-market protection is real | | Expiration time zone and date | Prevents last-minute confusion |

The cleanest comparison is a same-day quote from each lender, same lock period, same points target, same loan amount, and same estimated closing date. If one quote looks dramatically better, ask what assumption is different.

The simple borrower rule

If you are under contract, the payment works, and the lock period comfortably covers the closing date, locking is often the rational move. It turns a moving market variable into a known cost while you focus on underwriting, inspection, appraisal, and closing.

Floating can make sense when you have a long timeline, a strong budget cushion, and the discipline to accept that rates may move against you. But floating should be a deliberate risk choice, not a passive delay because nobody explained the lock.