Mortgage Rate Lock Extension APR Translator
See how expensive a mortgage rate-lock extension really is. Enter the fee charged, the loan amount being protected, and optionally the number of extra days granted to translate the charge into an annualised percentage rate comparable to market rate swings.
Informational use only. Confirm pricing impacts with your lender before locking decisions.
Examples
- $1,250 extension on a $420,000 loan for 30 days ⇒ equivalent APR 3.63%.
- $900 fee on a $350,000 loan for 15 days ⇒ equivalent APR 6.26%.
FAQ
What if the extension fee is rolled into closing costs?
You can still use the calculator. Enter the fee even if it is financed at closing; the APR translation shows the economic cost regardless of when you pay it.
How do I handle multiple extensions?
Run the calculator for each extension fee and sum the dollar impact or compare the highest APR against market volatility to see when switching products makes sense.
Does the calculator assume simple interest?
Yes. Lock extensions behave like a one-time charge, so the tool annualises the single-period cost without compounding.
Can I compare this to float-down options?
Yes. Use the APR output to weigh whether paying for a float-down is more cost-effective than extending the existing lock.
Additional Information
- Extension fees effectively act like very short-term interest. Annualising the charge lets you benchmark it against expected rate moves or alternative hedges.
- If your lender quotes the extension in basis points, multiply the locked loan amount by the basis points and enter the dollar figure here.
- Compare the output with the potential pricing change in par rates over the same window to decide if waiting or relocking is cheaper.
- Use the All-in Mortgage Cost calculators alongside this tool to evaluate whether buying points or renegotiating is more efficient.