Updated · Methodology: named formula library
Mortgage Refinance Calculator
Determine if refinancing your mortgage makes financial sense by comparing your current and new loan terms.
Your estimated monthly mortgage payment is $1,871 for a $300,000 loan at 6.4% over 30 years.
Why This Calculation Matters
The Mortgage Refinance Calculator helps you make better mortgages decisions by putting the math directly in front of you. Instead of relying on averages or guesswork, plug in your own numbers and see how the key inputs, rate, term, amount, and timing, interact. Small changes to any one of them can have outsized effects over years or decades.
How to Use This Calculator
- Enter your values in the input fields, each one has a label and help text explaining what to type.
- Results appear instantly as you type; there's no "calculate" button to press.
- Change any input to compare scenarios side by side.
All math happens in your browser. Nothing you type is sent to a server, saved, or shared.
Key Inputs to Get Right
The most important numbers are usually the interest rate and the time horizon. Over years or decades, small rate differences compound into large dollar differences, so it's worth sanity-checking the rate against current market data before acting on any result.
When Should You Refinance?
Refinancing replaces your current mortgage with a new one, ideally at a lower interest rate. The general rule is that refinancing makes sense if you can reduce your rate by at least 0.5-1%.
Break-Even Analysis
Calculate how many months of savings it takes to recoup closing costs. If you plan to stay in the home longer than the break-even point, refinancing likely makes sense.
Worked Example
$300k loan at 7% over 30 years
- principal
- 300000
- rate
- 7
- years
- 30
- Result
- $1,995.91/month
Monthly principal + interest. Total paid: $718,526.69.
When to Use This Calculator
- Model scenarios before making a major financial decision involving mortgages.
- Compare different inputs side by side to see how rate, term, or amount changes your outcome.
- Sanity-check numbers a lender, advisor, or spreadsheet has given you.
- Build a realistic financial plan grounded in your actual numbers, not averages.
Limitations & Common Mistakes
- Results are estimates, actual terms depend on credit, lender policy, taxes, and fees not captured here.
- Rates and prices change daily; recompute with current numbers before signing documents.
- Does not constitute financial advice. For major decisions, consult a licensed advisor.
Frequently Asked Questions
How does the Mortgage Refinance Calculator work?
Enter your loan amount (default: 300000) and any other inputs; the calculator instantly applies its mortgage refinance formula and shows the result with details. All math runs in your browser; nothing is sent to a server.
Is the Mortgage Refinance Calculator accurate for mortgages decisions?
It uses standard, documented formulas that match published references. For high-stakes mortgages decisions, verify the result against an authoritative source (industry calculator, professional advisor, or government data). The calculator is a planning estimate, not a substitute for professional judgment.
What inputs does the Mortgage Refinance Calculator require?
3 inputs: Loan Amount, Interest Rate, Loan Term (years). Each has a sensible default; replace with your own values to get a result tailored to your situation.
Can I bookmark or share the Mortgage Refinance Calculator?
Yes — the URL is stable: https://www.calcintel.com/calculator/mortgage-refinance. Inputs reset to defaults on each visit (no input is stored), so screenshot or copy the result if you want to preserve a specific scenario.
Related Calculators
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Amortization Schedule Calculator
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Interest Rate Calculator
Calculate the interest rate on a loan from the payment amount, principal, and term.
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Source: BLS Consumer Price Index, 2026.