What is a mortgage rate lock (and why it matters)
 Senior Mortgage Lender
Dana Briganti
Published on March 31, 2026
What is a mortgage rate lock (and why it matters)

What is a mortgage rate lock (and why it matters)

 

If you're in the process of buying a home, you've probably heard the term "rate lock." But what does it actually mean - and why is it so important?

A mortgage rate lock is a binding agreement between you and your lender that guarantees a specific interest rate for a set period of time - typically 30 to 60 days. This protects you from market fluctuations while your loan is being finalized, giving you peace of mind and helping you plan your monthly payment with confidence.


How Mortgage Rate Locks Work

Locking in Your Rate

Once you're under contract on a home, you have the option to lock in your interest rate (and any points tied to it). This ensures that even if market rates rise, your rate stays the same through closing.

Lock Period

Most rate locks last between 30 and 60 days, though longer options may be available depending on your lender and loan type.

Cost of a Rate Lock

Some lenders offer rate locks at no upfront cost, while others may charge a fee - or slightly increase the interest rate - to offset the risk of holding that rate for you.

What Happens If Your Lock Expires?

If your closing is delayed beyond your lock period, you may need to:

  • Pay a fee to extend the lock, or
  • Accept the current market rate (which could be higher)

Key Things to Consider

Float-Down Options

Some lenders offer a float-down option, which allows you to take advantage of lower rates if the market improves after you've locked. This can be a valuable safety net - but it's not always included, so be sure to ask.

When Should You Lock?

There's no perfect formula, but a good rule of thumb is to lock your rate when:

  • You're comfortable with the payment
  • The rate fits your budget
  • You're concerned rates may rise before closing

The Trade-Off

While a rate lock protects you from rising rates, it can also work the other way:

  • If rates drop, you're typically locked into your original rate
  • Unless you have a float-down option, you won't benefit from the decrease

Final Thoughts

A mortgage rate lock is all about certainty in an uncertain market. It gives you control over one of the most important parts of your home loan - your interest rate - so you can move toward closing with confidence.

If you're unsure about when to lock or what options are available, having a conversation with your lender can help you make the best decision for your situation.

 Senior Mortgage Lender
Dana Briganti Senior Mortgage Lender
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(646) 327-5184