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.
EveryCalc calculators are designed for fast, practical estimates with transparent inputs and no required account. We use plain formulas, visible assumptions, and related tools so visitors can check the result from more than one angle.
Results are informational only. For financial, tax, legal, medical, construction, or other high-impact decisions, verify the output against primary sources or a qualified professional.
Learn more about our review process on the EveryCalc methodology page.
How this calculator works
What this page estimates
This Mortgage Rate Lock Extension Calculator is built to give a quick, browser-based estimate for mortgage rate lock extension. 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. The inputs stay on the page during normal use, and the result should be treated as an estimate for planning, comparison, or education rather than professional advice.
Calculation approach
The calculator applies the standard relationship implied by the inputs, then formats the answer so it can be checked and reused. For finance tools, the most important step is using consistent units, rates, time periods, and assumptions before comparing the result with another calculator or outside quote.
Example workflow
For example, start with a realistic value you already know, change one input at a time, and watch how the answer moves. That makes it easier to tell whether the result is being driven by the main amount, the rate, the time period, or a unit conversion.
Practical checks
- Use current, real-world numbers when the result affects money, health, tax, or legal decisions.
- Run a low, base, and high case when the inputs are estimates.
- Check the related calculators below when the next decision depends on a different assumption.
How to interpret the mortgage rate lock extension result
Best use
Use the result as a planning number for comparing payments, rates, returns, tax reserves, or cash-flow choices before you request a quote or make a commitment.
Cross-check
Compare the answer with the contract, lender estimate, tax form, brokerage statement, payroll record, or invoice that will control the real-world outcome.
Watch for
Do not rely on a single optimistic rate, return, or fee assumption. Money pages work best when you run low, base, and high cases and keep professional advice separate from the estimate.
This page belongs to the Finance calculator library, so the answer should be read in the context of the decision you are modeling rather than as a universal rule.
Before relying on this mortgage rate lock extension estimate
Most calculator mistakes come from the inputs, not the arithmetic. Use this short audit before you reuse the answer in a spreadsheet, quote, application, or important conversation.
Confirm source numbers
Match balances, rates, fees, taxes, income, and payment dates against the lender quote, payroll record, tax form, statement, invoice, or contract.
Separate cash flow from total cost
A lower monthly payment can still cost more over time if fees, interest, taxes, or a longer term are hidden in the structure.
Run conservative cases
Test at least one higher-cost or lower-return case before using the output for a purchase, refinance, investment, loan, or tax decision.
Rerun this page when the rate, price, term, fee, tax rule, income, expense, or expected holding period changes.
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
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