MORTGAGE CALCULATOR

Rate Lock Scenario Calculator

See how a rate change would affect your specific payment — this tool doesn't predict where rates are headed, it shows your own exposure.

Run My Scenarios →

Market Average / Benchmark Rate

Freddie Mac PMMS national trend — not a rate available to you personally. Enter your lender's actual offered rate below.

Loading current mortgage rate data…

Your Rate Lock Scenarios

Results update as you change any input.

e.g. 0.75 for +0.75%, or -0.75 for -0.75% — added to the scenario table below.

Estimates are for educational purposes only · Not a rate prediction

Lock or Float? A Decision Framework

Not a call on where rates are headed — a check on your own situation.

1. How Close Is Your Closing Date?

A firm, near-term closing date makes it easier for a lock to actually cover your transaction. An uncertain or distant closing — common with new construction — raises the risk that your lock expires before you close.

2. How Much Budget Tolerance Do You Have?

Use the scenario table above to see what a rate increase would actually cost you per month. If your budget has little room to absorb that, locking removes that specific risk. If you have more flexibility, floating carries less consequence either way.

3. What Are Your Lender's Lock Terms?

Lock policies vary significantly by lender. Get the specific terms in writing before you decide — the questions below are a starting point.

Questions to Ask Your Lender Before Locking

  • 1How long is this rate locked, and what is the exact expiration date?
  • 2What fee, if any, applies to the lock itself?
  • 3If my closing is delayed, what happens — extension, repricing, or something else?
  • 4What does a lock extension cost, and who pays it?
  • 5Do you offer a float-down if rates fall after I lock — and what are the exact terms and cost?
  • 6Can I renegotiate or re-lock if my circumstances change?
  • 7If I need a longer lock period, does that change my rate or fees?
  • 8Would any lender credits I'm receiving change if I re-lock or extend?

Want the full lock/float guide with more depth? Read Mortgage Rates & Rate Locks →

The Formula This Calculator Uses

Monthly Payment Difference = P&I at Scenario Rate − P&I at Locked Rate
Worked Example

$360,000 loan, locked at 6.5% → P&I ≈ $2,275/mo. If rates were 0.25% higher (6.75%) → P&I ≈ $2,335/mo.
Difference ≈ $60/mo — about $716 over 1 year, or $3,582 over 5 years.

Frequently Asked Questions

Does this tool predict where mortgage rates are headed?

No. This calculator does not forecast future rates. It shows how your specific monthly payment would change under different hypothetical rate scenarios, so you can see your own exposure — not a prediction of what will actually happen.

Why only 1-year and 5-year estimates, not the full loan term?

Most homeowners refinance, sell, or otherwise don't keep the same loan for its entire original term. Projecting a rate difference across a full 30-year term can overstate real-world impact. 1-year and 5-year estimates give a more grounded sense of near-to-medium-term exposure.

What is the difference between the chart rate and my rate?

The chart above shows a national benchmark — the Freddie Mac Primary Mortgage Market Survey average. It is not a rate available to you personally. Your own rate depends on your credit, the property, loan program, lender, and points/credits — always use your lender's actual offered rate for your own calculations, not the benchmark.

Should I lock now or wait?

There's no reliable way to know whether rates will move up or down before your closing. The decision is generally better based on your closing date, whether your current rate fits your budget, the lock's cost, and your own risk tolerance — not a market prediction.

What if my closing date changes?

Ask your lender directly what happens if your closing is delayed beyond your lock expiration — policies vary widely, and this is especially important for new construction or any transaction with an uncertain settlement date.

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Buying a Specific Home?

Your rate is one part of the decision. Analyze the property itself with Reaixo before you commit.

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Educational Use Only: Reaixo is not a lender, mortgage broker, financial advisor, or loan originator. Calculations are estimates for informational and educational purposes only and may not include every cost associated with a mortgage. Rates, APRs, fees, taxes, insurance, mortgage insurance, eligibility, and loan terms vary by borrower, property, lender, loan program, and market conditions. Verify all figures and loan terms with a qualified lender and review your official Loan Estimate before making a financial decision.