# Rate lock

> A rate lock means your mortgage rate won’t change between the offer and closing, if you close in time. Typical lock periods, costs and what can break it.

URL: https://mail.mortgage-math-us.com/glossary/rate-lock/  
Last reviewed: 2026-10-29 · By the MortgageMath US Editorial team

## Quick answer

**A rate lock** (or lock-in) on a mortgage means your interest rate won’t change between the loan offer and closing, as long as you close within the lock period and nothing in your application changes. Locks are typically available for 30, 45 or 60 days, and sometimes longer.

## Key facts

| Fact | Value | Source | As of |
|---|---|---|---|
| Typical lock periods | 30, 45 or 60 days | [CFPB](https://www.consumerfinance.gov/ask-cfpb/whats-a-lock-in-or-a-rate-lock-en-143/) | Oct 28, 2026 |
| 30-year fixed average (used in the example) | 7.24% | [Freddie Mac Primary Mortgage Market Survey](https://www.freddiemac.com/pmms) | Week of Oct 29, 2026 |

## What a lock protects you from

Rates can move daily while a loan is processed. On a $300,000 30-year loan at 7.24%, the payment is $2,044. If rates rose half a percentage point before closing and you hadn’t locked, the payment would be $2,147 — $103 more a month, or $1,232 a year. A lock also fixes the [discount points](https://mail.mortgage-math-us.com/glossary/discount-points/) or [lender credit](https://mail.mortgage-math-us.com/glossary/lender-credit/) tied to that rate.

## What can change a locked rate

- **Expiration.** If closing slips past the lock date, extending it may be expensive. Ask what extensions cost before you choose a lock period.
- **Changes to your file.** A different loan amount, a lower appraisal, a new credit score or a change in income can change the price.
- **Floating down.** If rates fall after you lock, you usually keep the higher rate unless your lock includes a float-down option.

Page 1 of the [Loan Estimate](https://mail.mortgage-math-us.com/glossary/loan-estimate/) shows whether your rate is locked and when the lock expires. Plan the lock around your [closing](https://mail.mortgage-math-us.com/glossary/closing/) date. See [how a rate lock works](https://mail.mortgage-math-us.com/blog/how-a-rate-lock-works/) and the [mortgage rates guide](https://mail.mortgage-math-us.com/buying/mortgage-rates/).

## Sources

- [Freddie Mac Primary Mortgage Market Survey](https://www.freddiemac.com/pmms) — 30-year fixed rate, national weekly average (Week of Oct 29, 2026)
- [CFPB](https://www.consumerfinance.gov/ask-cfpb/whats-a-lock-in-or-a-rate-lock-en-143/) — Typical rate lock periods (Oct 28, 2026)
- [CFPB: What’s a lock-in or a rate lock on a mortgage?](https://www.consumerfinance.gov/ask-cfpb/whats-a-lock-in-or-a-rate-lock-en-143/)

_General information, not financial advice._