Finance category
Mortgage, loan, investing, tax, and money calculators.
Mortgage Rate Lock Extension Calculator
If your close is delayed past the rate lock expiration, you pay an extension fee (0.0625%-0.25% per extension) or re-lock at current market rate. This calculator compares both.
Recommendation
Extend lock
Extension cost
$1,000
Lifetime cost if re-lock at market
$47,858
Monthly payment difference
$133
How the math works
$400K locked at 6.5%, market at 7%, 14 days extension needed: extension fee $1,000 (2 weeks × 0.125%). Lifetime cost of re-locking at 7%: ~$47K higher. Extend easily wins.
If market rate has dropped below your lock, just let it expire. Re-lock at lower rate — net win. If rates rose, extend.
How to Use
- Enter locked rate, current market rate, and extension fee.
- Enter days of extension needed.
- See which path is cheaper.
Frequently Asked Questions
What does extension cost?
$0.0625%-$0.25% per extension week (varies by lender). Some offer free 7-day extensions. On $400K loan at 0.125% = $500 per week of extension.
Does lock drop if rates fall?
Most locks are one-direction: locks protect against rate rise but don't float down. Some 'float-down' locks exist — typically 0.125% extra cost upfront.
What if I miss the lock?
Re-lock at current market rate. If rates dropped, you win. If rose, you pay higher rate for 30 years — expensive. Extend if rates are rising.
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Mortgage Rate Lock Calculator
Compare a locked rate to today's market rate, account for extension fees, and see lifetime savings or cost from locking when you did.
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