Rate Locks Explained
A rate lock freezes your rate and points against a market that moves every day — for a set number of days, tied to your specific loan file. It's insurance against a rate spike while you close. Like any insurance, it isn't free, and it comes with a clock.
What a lock actually holds
A lock pins the note rate and its price (the points or credit at that rate) for a window — commonly 30, 45, or 60 days. It's attached to a specific property and loan amount, so it isn't a rate you can shop around; it's a commitment between you and that lender. If the market rises during the window, you're protected. If it falls, you're generally stuck at the locked rate unless your lock has a float-down.
The lock has a price baked in
Longer locks cost more, because the lender carries market risk for longer — a 60-day lock prices a touch worse than a 15-day lock for the identical rate. You rarely see a separate "lock fee"; the cost is built into the rate or points on the rate sheet. So a quote is only meaningful alongside its lock period: a sharp rate you can't actually close inside isn't a real quote.
Lock or float?
To float is to bet the market improves before you close. The honest truth from twenty years of watching it: no one — not your loan officer, not the pundits — reliably times the bond market that sets mortgage rates. Floating can win, but it's a gamble with your closing on the line.
Float-downs and extensions — read the fine print
A float-down lets you re-lock lower if rates drop after you lock, usually for a fee or a minimum improvement threshold; not all locks offer one, and the terms vary. An extension is what you pay if closing slips past your lock's expiration — often a per-day charge. If your timeline is uncertain, ask about both before you lock, not after the window is closing. Then check where the market sits on our rate board so you're deciding against real numbers.
By L.W. Martin, Founder — 20 years in the mortgage business, including 15 running his own brokerage. About → · Updated August 2026.