Mortgage Rate Locks: When and How to Lock Your Rate

Mortgage rates can move a quarter point in a single news cycle. A rate lock takes that risk off the table — for a price. Here’s how rate locks actually work in 2026, when locking pays off, and the optional features worth considering when the market is volatile.

What a rate lock is

A rate lock is a written commitment from a lender to honor a specific interest rate (and usually a specific set of points and fees) for a set number of days, regardless of what happens to market rates in the meantime. Common lock periods are 30, 45, 60, and 90 days, with longer locks available for new construction or unusual closing timelines.

Locks are typically offered after you’ve been preapproved and either have a property under contract or, in some cases, after the loan application but before identifying a property (“float-down” or “lock-and-shop” programs).

How much a lock costs

Most locks are advertised as “free,” but they aren’t — the lender prices the lock period into the rate itself. Longer locks get higher rates. Typical 2026 spread:

This is why your lock period should match your real closing timeline — not be padded for safety. A 60-day lock when you’ll close in 35 days is paying for protection you didn’t need.

When to lock

The simple rule: lock when you have a property under contract and a reasonable estimate of when you’ll close. The math is asymmetric — a quarter-point increase on a $350K loan over 30 years is about $20,000 in extra lifetime interest. A quarter-point decrease saved by floating earns you the same amount. But the downside of a big spike is much worse than the upside of a small drop, because a spike can also push your DTI out of qualifying range.

Specifically, lock when:

• You’re under contract and your closing date is within the available lock periods (almost always).
• Rates are trending up and the move is being driven by macro events likely to continue (Fed meetings, inflation prints, treasury auctions).
• You’re at the edge of your DTI and a 0.25% increase would disqualify the loan.
• You’re in an FHA, VA, or USDA loan where re-approval after a rate spike is paperwork-intensive.

When floating might make sense

Floating means leaving the rate unlocked, watching the market, and hoping it falls before you have to lock. It’s a calculated bet, not a strategy:

• Rates have been falling for several weeks on consistent macro news (cooling inflation, dovish Fed signals, slowing employment).
• You have margin in your DTI and can absorb a 0.25% jump if it goes the wrong way.
• Your closing date is far enough out that you have time to react.
• You have a refinance plan B — you’d just refinance later if rates drop further.

Honest take: most people who try to time the market on a rate lock end up worse off than if they’d just locked at the first reasonable rate. Day-trading mortgage rates is a bad use of cognitive energy when you’re also packing boxes and arguing with the home inspector.

The float-down option

A float-down rider lets you take advantage of falling rates after you’ve locked. The mechanics vary by lender, but typical terms:

• You can use it once during the lock period
• Rates must drop by at least 0.25% from your locked rate
• Costs 0.125–0.50% of the loan amount, paid up front or rolled into the rate
• Window is usually capped — e.g. only available 15+ days before closing

On a $350,000 loan, a 0.25% float-down fee is $875 up front. A 0.5% rate drop on the same loan saves about $115/month, or $1,380/year. Float-down riders are worth considering when:

• You’re locking 45+ days before closing and rates are at a local high.
• You’re locking just before a Fed meeting where a cut is on the table.
• You’re building new construction with a 90-day or longer timeline.

They’re probably not worth it for a 30-day lock in a stable rate environment.

Lock-and-shop programs

A few lenders offer locks before you’ve identified a property — typically 60–90 days, with a 0.25–0.50% rate premium. Useful in two situations:

• You’re shopping in a market where rates are rising fast and you want to know your maximum payment before bidding.
• You’re moving cross-country and need budget certainty for your house hunt.

The downside: you’re paying a premium even if you don’t find a home, and these locks usually require a property appraisal and full underwriting once you go under contract — which can sometimes change the offered rate.

What happens if your lock expires

Lock expiration is one of the most expensive surprises in homebuying. If you can’t close before the lock expires, you have three options:

1. Lock extension. Lenders typically charge 0.125–0.375% of the loan amount per 7–15 day extension. On a $350K loan, that’s $437–$1,312 per extension. If the delay is the lender’s fault (slow appraisal review, processing backlog), some lenders will eat the cost — ask.
2. Re-lock at current market rates. If rates have fallen, this is often better than extending. If they’ve risen, it’s painful — and the lender will use the higher of the original locked rate or current market rate (the “worse-of” rule that exists specifically to prevent gaming).
3. Find a new lender. If the original lender’s delays caused the expiration and they refuse to absorb the extension cost, switching is sometimes cheaper. Tight, but possible if the delay is identified early.

Reading your lock confirmation

When you lock, you’ll get a written confirmation. Verify these five items in writing — verbal promises don’t survive a market move:

1. The locked interest rate
2. Discount points and origination charges (must be locked too)
3. Lock expiration date (and any time-zone fine print)
4. Loan program (a 30-year conventional lock doesn’t cover an FHA loan)
5. Loan amount range — most locks allow ±5% movement; outside that, the lock can void

If your purchase price changes during negotiation, confirm whether the new loan amount stays inside your lock’s tolerance.

Locking in a refinance

Rate locks for refinances follow the same rules but with no purchase contract pressure. Most refinance closings take 30–45 days, so a 30-day lock at today’s baseline rate is usually appropriate. If you’re considering refinancing, walk through our refinance break-even guide first to confirm the math actually works before locking — and use our refinance calculator to compare lock-day rate scenarios.

The most common rate-lock mistakes

• Padding the lock period “to be safe.” A 60-day lock when you’ll close in 30 days costs you 0.125–0.25% of rate forever. Match the lock to your actual timeline.
• Locking on the first quote. Lock with the lender you’re using, but get rate quotes from 2–3 lenders within 14 days first. The spread between competitive quotes is often 0.125–0.25%.
• Trying to time the market. If the rate is workable for your budget and you’re in contract, lock. The peace of mind is worth the lost upside of a small drop.
• Not getting the lock in writing. Verbal locks aren’t real locks. Insist on the confirmation document.
• Forgetting that fees are part of the lock. A competitor offering 0.25% lower might also be charging $3,000 more in fees. Use the “In 5 Years” box on the loan estimate to compare apples to apples.

Bottom line

Lock when you’re under contract and the rate is workable. Don’t pay for more lock days than you need. Get it in writing, verify the points and fees are locked too, and confirm the loan amount tolerance. If rates fall significantly after locking, evaluate a float-down rider or a re-lock with another lender — but don’t chase small moves. Closing on time at a sensible rate beats closing late at the perfect one.

See what each rate means for your payment

Run different rates side-by-side in our mortgage calculator to quantify exactly how much an eighth or quarter point matters on your loan amount. The difference between a 6.50% and 6.75% lock on a $350K loan is real money — about $20,000 over the life of the loan.