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How Long Should I Lock My Mortgage Rate? A Banker's Honest Answer

By Ziya Y. · 23 Years Banking & Mortgage · Updated May 2026
Rate lock decisions feel high-stakes because they are. Here's how I'd think about it.

The Basic Options

Most lenders offer 30, 45, or 60-day locks. Longer locks cost more — either through a higher rate or an explicit fee (typically 0.125-0.25% of loan amount per 15 days beyond 30).

The Honest Rule of Thumb

Lock for longer than you think you need. The average mortgage takes 30-45 days to close from application. But underwriting delays, title issues, and appraisal problems are common. I watched more locks expire than I can count — and extensions cost money or require re-pricing.

When to Float (Not Lock)

Floating makes sense only when rates are trending meaningfully downward AND you have financial flexibility. If a 0.25% rate increase would kill your affordability, lock immediately. The upside of floating rarely justifies the risk for most buyers.

What Happens When Your Lock Expires

Two options: extend (usually costs 0.25-0.375 points) or re-lock at current market rates. If rates rose while you were in underwriting, you pay the higher rate. If rates fell, some lenders offer "float-down" provisions — but read the fine print.

The Float-Down Option

Some lenders offer float-down locks: you're protected if rates rise, but you can lock at a lower rate if the market drops by a minimum amount (usually 0.25-0.5%). These cost 0.5-1 point but can be worth it in volatile markets.

My Actual Recommendation

For most buyers in a purchase transaction: lock for 45-60 days at closing. The cost difference is minimal and the protection is significant. For refinances with flexible timelines: floating for 2-3 weeks to watch trends is reasonable if you're not rate-dependent.

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Ziya Y.
23 years in banking and mortgage underwriting. Founder of FinanceRateCalc.com. Built Zai — a free AI mortgage advisor trained on real bank logic.

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Not financial advice. Educational content based on 23 years of mortgage industry experience.

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