I’m Michael DiVita — DRE #01372066 | NMLS #241655, DiVita Home Finance (DRE #01818285 | NMLS #323700), Tiburon, CA. Call (800) 239-1103.

Mortgage Rate Locks: How They Work and When to Lock Your Rate

A mortgage rate lock is a lender’s commitment to hold a specific interest rate for a defined period while your loan is in process. In a volatile rate environment, knowing when and how to lock can save or cost you thousands of dollars. Here’s how rate locks work and the strategy behind optimal lock timing.

What a Rate Lock Does

When you lock your rate, the lender guarantees that rate for a specified number of days — typically 15, 30, 45, or 60 days. If market rates rise during your lock period, your rate stays the same. If rates fall, you’re locked in at the higher rate unless your lock includes a float-down provision. The lock buys certainty at the cost of flexibility. Without a rate lock, your final rate isn’t determined until close to funding — acceptable if rates are declining, risky if rates are volatile or rising.

When to Lock: Key Timing Considerations

Lock when rates are rising and you have a clear closing timeline. If bond markets are trending upward and you’re under contract with a defined escrow period, locking early protects you from additional increases. Float when rates are clearly declining and you have time — but understand that rates can reverse overnight on economic data. Most California buyers lock at contract or shortly after, matching the lock period to their expected closing date. For a 30-day escrow, a 30-day lock works. For extended contingency periods or complex transactions, a 45-day or 60-day lock provides a buffer. Choosing too short a lock and needing an extension is common and avoidable with honest timeline planning.

Rate Lock Costs and Extensions

Short locks (15–30 days) are typically free. Longer locks (45–60 days) often cost 0.125%–0.25% in points or a slightly higher rate. Lock extensions — when your escrow takes longer than expected — cost money too, usually 0.125%–0.25% per additional week. Choosing the right lock length upfront avoids extension fees. California escrows are often delayed by appraisal turnaround times, HOA document collection on condos, title issues on estates, and last-minute underwriting conditions. Building a buffer into your lock period is almost always worth the small cost versus risking an expensive extension or losing your lock entirely.

Float-Down Provisions

Some lenders offer a float-down option: you lock at today’s rate, but if rates drop by more than a specified amount (typically 0.25%–0.5%) before closing, you get the lower rate. Float-downs usually cost 0.25%–0.5% upfront. They’re most valuable when you’re locking a longer period in a volatile market where rates might move significantly in either direction. Ask your broker whether a float-down is available and whether the math justifies the premium for your specific loan and lock period.

Lock Periods and Closing Timeline Planning

Choosing the right lock period requires honest assessment of your closing timeline — then adding a buffer. California purchase escrows are typically 21–30 days for conventional loans and 30–45 days for FHA/VA. Jumbo purchases, self-employed borrowers, and complex income situations often run 30–45 days regardless of loan type. If your escrow target is 30 days, a 45-day lock costs a little more but provides real protection. Communicate specifically with your broker about your expected timeline. The broker who sets the lock based on what they hope will happen, rather than what is realistic, will cost you extension fees when escrow runs long — which in California happens regularly.