When you lock a mortgage rate, you are agreeing to whatever rate the lender quotes today, even if rates drop next month. A float-down option flips that. It lets you lock the rate, then capture a lower rate if the market falls before closing, usually for a fee.
Float-downs can save thousands of dollars over the life of a loan, but they only make sense in specific situations. Here is how they work, what they cost, and when to ask your lender about one.
What a mortgage rate lock does on its own
A standard rate lock pins your interest rate at today's number for a set period, typically 30 to 60 days. If rates rise during that window, you keep the locked rate. If rates fall, you also keep the locked rate, which now looks worse compared to what you could have gotten.
Most lenders offer rate locks at no upfront fee but charge slightly higher rates for longer locks. A 60-day lock might be 0.10% higher than a 30-day lock, all else equal.
Rate locks exist because mortgage rates can move 0.25% to 0.50% in a single week. Without a lock, the rate you saw when you applied may be gone by closing day, which can change your monthly payment by $50 to $200.
How a float-down adds flexibility
A float-down option is an add-on to a rate lock. It gives you the right to switch to a lower rate one time during the lock period if the market moves in your favor.
The details vary by lender, but a typical structure looks like this. You lock at, say, 6.875%. The lender offers a float-down for a fee of 0.25% of the loan amount, paid at closing. If the market rate drops to 6.50% or lower at any point before closing, you can exercise the float-down and lock at the lower rate.
Some lenders require the rate to drop by a minimum amount, often 0.25% to 0.50%, before you can exercise. Some allow only one float-down, others allow multiple windows.
What float-down options cost
Three common pricing structures.
Upfront fee. A flat charge, often 0.25% to 0.50% of the loan amount, paid at closing whether or not you use the float-down. On a $300K loan, that is $750 to $1,500.
Higher initial rate. No upfront fee, but the locked rate is 0.10% to 0.25% higher than a standard lock. You pay through a higher rate even if you do not use the float-down.
Float-down spread. The float-down lets you capture only part of the market drop. If rates fall 0.50%, you might get 0.375% lower than your locked rate, not the full drop.
Read the float-down terms carefully. Some lenders bundle them into the rate lock for free as a marketing perk, especially in high-rate environments. Others charge real money for the option.
When a float-down pays off
Four scenarios where it makes sense.
When rates are widely expected to drop, like during a Federal Reserve easing cycle. If the Fed cuts rates 0.25% to 0.75% during your lock window, a float-down can save you tens of thousands over a 30-year mortgage.
When the lock period is long, 60 to 90 days, giving more time for rate movement.
When the loan amount is large. The percentage cost of the float-down stays the same, but the dollar savings on a lower rate scale up. On a $500K loan, a 0.25% rate drop saves about $80 a month.
When you have low risk tolerance for missing a lower rate. Some borrowers value the optionality even if the expected value is roughly neutral.
When to skip the float-down
In rising-rate environments, the float-down is unlikely to pay off. If rates are expected to climb during your lock window, the standard lock is the better deal, since you already captured today's lower rate.
On short lock periods of 15 to 30 days, the chance of a meaningful rate drop is small. The float-down fee probably exceeds the expected savings.
On small loans of $100K or less, the dollar savings even on a favorable rate drop may not justify the upfront fee.
How float-downs interact with your closing timeline
Most float-downs require you to be actively moving toward closing. If your loan is in underwriting and the appraisal has come back, the lender will honor the float-down. If your file is stalled or you have delayed closing, some lenders restrict the option.
Also, the float-down has to be exercised before the rate lock expires. If your lock expires before rates drop enough, you lose the option. Watch the calendar.
What credit score does for the rate you lock
Your credit score sets the starting rate the lender quotes. Higher scores get lower rates. In 2026, a 760+ score typically gets the best advertised rate, a 700 to 759 score adds 0.25% to 0.50%, and a 640 to 699 score adds 0.75% to 1.50%.
A float-down can capture market movement, but it cannot capture the gap caused by a low credit score. The best lever before applying is your credit score itself.
Build credit before locking
If your closing is six months out, you have time to improve your score. The Self.Inc Credit Builder Account works like a savings tradeline that reports on-time payments to all three bureaus. The Self Visa® Credit Card adds a positive revolving tradeline once you unlock it through the builder.
Dovly's AI-powered credit engine can dispute errors on your report, which often unlocks quick score gains. Many borrowers find 10 to 30 errors on a fresh credit report, especially around old loan accounts and authorized user history.
Free credit monitoring through Creditship lets you watch your score move in real time as you prep for the mortgage application. Each 20-point score improvement can mean a 0.125% to 0.25% lower rate, which on a $300K mortgage is $25 to $50 a month for 30 years.
Negotiating the float-down
Float-downs are often negotiable. If you have a strong loan file and the lender wants the business, ask for a free float-down or a reduced fee. Compare offers from two or three lenders to leverage one against another.
Mortgage marketplaces and broker shops can speed this up by showing multiple offers at once. Always compare the all-in cost, including the rate, lock fee, float-down fee, points, and closing costs, not just the headline rate.
Frequently Asked Questions
How much does a float-down option cost?
Float-down fees typically range from 0.25% to 0.50% of the loan amount, paid at closing. On a $300K mortgage, that is $750 to $1,500. Some lenders bundle the option into the rate lock for free, especially during high-rate environments. Always ask whether the lender will waive or reduce the fee.
When should I exercise a float-down option?
Exercise when the market rate has dropped by at least the float-down trigger, usually 0.25% to 0.50% below your locked rate, and you still have time before closing. The savings compound over the life of the loan, so even a one-time 0.25% rate improvement can save thousands. Confirm with your lender that you meet the minimum movement requirement before requesting.
Can I float down more than once during the lock period?
Most lenders allow only one float-down during the lock window. A few offer multiple float-downs or unlimited float-downs for a higher fee. Read the terms in your rate lock agreement to see exactly how many times the option can be exercised.
Does a rate lock or float-down affect my credit score?
No. Locking your rate or exercising a float-down does not pull a new hard inquiry on your credit report. The hard pull happens at the initial mortgage application. The float-down is an option within an already-locked loan and does not require an additional credit check.
