What's the difference between locking and floating a mortgage rate?

Locking fixes your interest rate for a set period, usually 30 to 45 days, so it can't go up before closing even if the market moves. Floating means you're not locked at all, so your rate moves with the market until you decide to lock in, which can help if rates are falling but exposes you if they rise.

What is a float-down option on a mortgage rate lock?

A float-down is an add-on to a standard rate lock that lets you capture a lower rate if the market drops a real amount after you lock, instead of being stuck with your original number. Most lenders require rates to fall by at least a quarter point before you can use it, and it typically costs extra, often a quarter to a full point of the loan amount.

Should a Houston buyer pay for a float-down right now?

If your lender offers one and your closing is more than 30 days out, it's often worth the cost given how much Houston-area rates have moved over the past year, from the mid-6% range toward 7% by some lender reports. Ask for the exact trigger and fee in writing before you decide, since both vary by lender.

How long does a typical mortgage rate lock last?

Most standard locks run 30 or 45 days, often at no extra cost, timed to match your expected closing date. A longer lock, 60 or 90 days, is available from many lenders but usually comes with a fee, so match the lock length to your real contract timeline rather than padding it as a precaution.

What happens if your rate lock expires before you close?

Most lenders charge an extension fee to keep your locked rate active past the original expiration date, and the fee usually grows the longer the delay runs. If your closing is slipping, ask your lender about extension costs well before the lock expires, not the day it does.

Market

Should You Lock or Float Your Mortgage Rate Buying a Houston Home Right Now?

October 13, 2026

A Houston homebuyer signing mortgage paperwork at a sunlit kitchen table with a laptop showing rate information

Lock your rate, and ask your lender about a float-down option if your closing is more than a few weeks out. Mortgage rates have moved a real amount this year, with some lender reports showing the 30-year fixed running near 6.4% in early summer and closer to 6.95% by September, so betting on which direction rates go next between now and your closing date is a real gamble, not a safe assumption either way.

What Locking and Floating Mean

A rate lock fixes your interest rate for a set window, typically 30 or 45 days, timed to your expected closing date. Once it’s locked, your rate can’t move even if the broader market does, in either direction. Floating means staying unlocked, letting your rate track the market day to day until you choose to lock, which can work out if rates are genuinely falling but leaves you exposed if they climb instead. Should Houston Buyers Wait for Rates to Drop Before Buying in 2026? covers the bigger decision about timing your purchase around rates; locking or floating is the narrower decision about timing your rate once you’re already under contract.

The Float-Down: Locking Without Fully Committing

A float-down is an add-on most lenders offer, though not all, that lets you keep a locked rate while still capturing a meaningfully lower one if the market drops before closing. It’s not automatic and it’s not free:

Most lenders require rates to fall by at least a quarter point before you can exercise it.
The cost typically runs a quarter to a full point of your loan amount, paid up front.
Not every lender offers it, so ask specifically, and get the exact trigger threshold and fee in writing rather than taking a verbal estimate.

For a buyer locking a rate this fall, after rates have swung in both directions over a matter of months, a float-down buys real peace of mind. It’s worth pricing out against your specific loan amount before you decide it’s worth the fee.

What’s Driving the Swings Right Now

Houston-area reporting has shown real disagreement in recent months, which tells you something on its own: one lender-cited figure put the 30-year fixed near 6.4% in early summer, another showed it closer to 6.95% by September, citing Freddie Mac data. That’s not a data error so much as a market that’s been moving in real ways, which is exactly the environment where locking without a float-down means hoping you guessed right, and floating with no lock at all means hoping the market keeps moving your way until the day you close.

Match the Lock Length to Your Timeline

A lock that’s too short forces an expensive extension if your closing slips even a few days. A lock that’s unnecessarily long usually costs more than it needs to. Pull your expected closing date from your contract, add a reasonable buffer for anything that could realistically push it, and lock for that window specifically rather than defaulting to whatever period your lender offers first. Are Mortgage Discount Points Worth It for Houston Buyers? walks through a related upfront-cost decision that’s worth weighing in the same conversation with your lender, since both affect what you’re paying for your rate.

Our Take

The Move Live Love TX Team™ walks buyers through this exact decision on nearly every Houston purchase right now, and we don’t tell clients to guess on rates, because nobody guesses right on a consistent basis, not us, not the lenders, not the forecasters who keep revising their own 2026 predictions. What we do tell them is to lock with a float-down whenever the fee makes sense for the loan size, so a drop in the market works in their favor instead of being something they only read about after the fact. Our Buyer’s Guide covers the rest of what to line up with your lender before you’re under a closing-date deadline.

Frequently Asked Questions

What's the difference between locking and floating a mortgage rate?: Locking fixes your interest rate for a set period, usually 30 to 45 days, so it can't go up before closing even if the market moves. Floating means you're not locked at all, so your rate moves with the market until you decide to lock in, which can help if rates are falling but exposes you if they rise.
What is a float-down option on a mortgage rate lock?: A float-down is an add-on to a standard rate lock that lets you capture a lower rate if the market drops a real amount after you lock, instead of being stuck with your original number. Most lenders require rates to fall by at least a quarter point before you can use it, and it typically costs extra, often a quarter to a full point of the loan amount.
Should a Houston buyer pay for a float-down right now?: If your lender offers one and your closing is more than 30 days out, it's often worth the cost given how much Houston-area rates have moved over the past year, from the mid-6% range toward 7% by some lender reports. Ask for the exact trigger and fee in writing before you decide, since both vary by lender.
How long does a typical mortgage rate lock last?: Most standard locks run 30 or 45 days, often at no extra cost, timed to match your expected closing date. A longer lock, 60 or 90 days, is available from many lenders but usually comes with a fee, so match the lock length to your real contract timeline rather than padding it as a precaution.
What happens if your rate lock expires before you close?: Most lenders charge an extension fee to keep your locked rate active past the original expiration date, and the fee usually grows the longer the delay runs. If your closing is slipping, ask your lender about extension costs well before the lock expires, not the day it does.