Should I Lock My Mortgage Rate or Wait?

Every borrower I work with asks some version of this in the first week: "Should I lock now or wait — rates might come down."

The short answer: you can always lock; you can rarely unlock. The longer answer is that whether to lock depends on three things — your timeline, the rate trend, and whether your lender offers a float-down. Let me walk through how I think about it.

What "locking" actually does

When you lock a rate, the lender commits to honor that rate for a set window (usually 15, 30, 45, or 60 days). They take on the risk that the market moves. If rates go up tomorrow, you keep your locked rate. If rates drop, you keep your locked rate — unless your lock has a "float-down" option (rare on purchase, more common on refi).

The lender prices this risk into the rate sheet. A 60-day lock typically costs ~0.125% more than a 30-day lock. A 90-day lock can run 0.25%+ higher. So locking longer than you need is just a tax on indecision.

When to lock

• You have an accepted purchase contract with a closing date inside the lock window. Lock the day the contract is signed. The downside of a worse rate tomorrow is much bigger than the upside of a slightly better one.
• You're inside 30 days of closing on a refi and the math already works. The deal is in the bag — don't bet your closing date on a hypothetical 0.125% improvement.
• Rates are clearly trending up and your closing is firm. The trend matters more than the daily noise.

When to float

• You're 60+ days from closing on a purchase with no real lock-window option that fits. Floating until you're 45 days out lets you lock at the cheaper short-window price.
• You're well qualified and the trend is clearly down. This is rare — even when "rates are coming down" in the news, the day-to-day moves are noisy. If you're saving 0.0625% per week and might gain 0.5%, the math says wait. But the gain isn't guaranteed.

Float-down — what it actually buys you

A float-down clause says: "If the market improves by X amount before closing, you can re-lock at the better rate, usually with a fee or a slightly worse starting rate." Each lender prices this differently. On a refi with a 60-day lock, a float-down typically adds 0.125% to the starting rate but caps your downside.

This is worth it when:

• You're locking 45+ days out and rates are volatile
• A 0.25%+ improvement is realistic in the window

It's not worth it when:

• You're 21 days from closing — the window is too short to meaningfully improve
• You're buying the "rate will surely drop next week" narrative without data

The real cost of waiting

Rates can move 0.25%+ in a single day on a CPI release or Fed meeting. On a $600k loan, that's about $95/month difference, or $34,000 over 30 years. The "I'll wait until next week" decision can cost more than the entire closing-cost package.

Meanwhile, the upside of waiting is usually capped at 0.125-0.25% in a normal market. The asymmetry isn't in floating's favor.

What I actually tell my borrowers

If you have a contract and a closing date inside 30-45 days: lock. The peace of mind alone is worth it, and a 0.125% improvement isn't going to change your life.

If you're a refi with a flexible timeline and rates are clearly trending down: float with a hard deadline. Pick a date — "I lock by the 15th regardless" — and stick to it.

If you don't know which trend rates are in: stop watching daily. Watch the 30-day moving average. Daily moves are noise; weekly moves are signal.

The mistake I see most

Borrowers who try to time the bottom and end up locking at a worse rate than they could have had three weeks earlier. Mortgage rates don't bottom-tick like stocks — by the time everyone agrees "rates are great," the rate sheets have already moved.

If the math works today, lock today. The 0.0625% you might save by waiting is rarely worth the stress.

Want me to look at your specific scenario and tell you whether to lock or float? Book a 30-min call or text (858) 531-2442 — I'll show you the rate sheet for your file and walk through the math.