Refinance Calculator
The Refinance Calculator helps you decide if refinancing your mortgage or any loan is worth it. It compares your current loan against a new refinanced loan and tells you the monthly savings, break-even point (how many months until you recoup closing costs), and total lifetime savings — the three numbers you need to make a smart refinancing decision.
Educational estimate. Calculator results are for planning and information only, not financial, tax, medical, legal, or engineering advice. Verify important decisions with official sources or a qualified professional.
Refinance Calculator
Break-Even Analysis & Lifetime Savings
📐 Formula & Method
Monthly Payment Formula
Applied to both the current loan and new refinanced loan to find monthly payments.
Monthly Savings
The reduction in your monthly payment. Note: if you extend the term while reducing the rate, your savings may be partially offset by more years of interest.
Break-Even Point
The number of months it takes for your accumulated monthly savings to exceed the upfront costs of refinancing. Stay in the home/keep the loan beyond this point and refinancing is financially beneficial.
📋 How to Use
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1
Enter your current loan balance (the amount you still owe).
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2
Enter your current interest rate and remaining term in years.
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3
Enter the new interest rate you've been offered.
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4
Enter the new loan term — consider 15 or 20 years if you can afford higher payments.
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5
Enter estimated closing costs (typically 2-5% of the loan amount).
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6
Click Calculate to see monthly savings, break-even months, and total interest comparison.
💡 Key Insights
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A common rule of thumb says refinance once you can drop your rate by at least 0.75–1.00% — but the real test is your break-even period vs how long you'll stay in the home.
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Rolling closing costs into the new loan saves cash today but raises lifetime interest. Paying them up front almost always wins if you keep the loan for 5+ years.
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Refinancing resets your amortization clock. Five years into a 30-year loan, a fresh 30-year resets you to year 1 — often more interest paid even at a lower rate.
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Consider a cash-out refinance only if you're using the proceeds for a financially productive purpose (home improvement, high-interest debt payoff, investments).
🧮 Worked Examples
Refinance saves $312/mo
Refinance a $320,000 balance from 7.25% / 28 years remaining to 6.00% / 30 years with $4,000 closing costs.
📊 How to Interpret Your Result
Break-even ≤ 24 months
Strong refinance — costs recovered within 2 years.
Break-even 24–48 months
Only refinance if you're confident you'll stay in the home well past the break-even date.
Break-even > 48 months
Marginal benefit. Re-shop lenders or wait for a better rate.
⚠️ Common Mistakes to Avoid
Comparing only the monthly payment.
Fix: Lower payments often come from extending the term. Compare lifetime interest too.
Ignoring closing costs by rolling them in.
Fix: Always model both paid-upfront and rolled-in scenarios — the break-even differs significantly.
Refinancing without a clear ownership horizon.
Fix: If you might sell in 2–3 years, a no-closing-cost refinance (higher rate, zero fees) may beat a traditional refinance.
🎯 Who This Calculator Is For
Homeowners when rates drop 0.75%+
See if your monthly savings exceed closing costs within your stay horizon.
Owners with improved credit score
A 60+ point credit jump can unlock a 0.25–0.50% rate improvement.
Adjustable-rate borrowers approaching reset
Lock in a fixed rate before your ARM resets to a potentially much higher rate.
When Does Refinancing Make Sense?
Refinancing makes financial sense when the long-term interest savings exceed the upfront costs of refinancing. The traditional rule of thumb is to refinance when you can reduce your rate by at least 1% — but the more accurate test is the break-even calculation: divide your closing costs by your monthly savings to find how many months until you break even.
If you plan to stay in your home longer than the break-even period, refinancing saves you money. If you'll move before the break-even point, you'll lose money on the deal. For example, if closing costs are $5,000 and you save $200/month, your break-even is 25 months (about 2 years). If you plan to stay 10+ years, refinancing at that point would save $24,000–$29,000 over the remaining period.
In the UK, remortgaging (the equivalent of refinancing) is common at the end of an initial fixed rate period (typically 2 or 5 years). When your introductory rate expires, your lender moves you to the standard variable rate (SVR), which is typically 1–3% higher. Remortgaging to a new fixed deal at a competitive rate is standard practice. Key costs include arrangement fees (£0–£2,000), legal fees (~£300–£800), and a valuation fee (~£150–£400).
Even if your new loan extends the term (e.g., resetting to a new 30-year loan), the lower rate can dramatically reduce your monthly payment. However, be aware that extending the term means you pay interest for longer — always compare the total lifetime interest paid, not just the monthly payment.
🔬 Methodology & Accuracy
Formula: Both the current and proposed loans are amortized independently. Break-even months = closing costs ÷ monthly savings. Lifetime savings = current remaining interest − new total interest − closing costs.
Data sources: Freddie Mac Primary Mortgage Market Survey; CFPB closing cost disclosures.
Last reviewed: January 2026 · Accuracy: Results are precise to two decimal places using IEEE-754 double-precision arithmetic. Intended for educational and planning use only.
For informational purposes only. Results are estimates based on the inputs and formulas provided. For financial, tax, medical, or legal decisions, consult a qualified professional. Rates and regulations change — always verify current figures with official sources.
Accuracy & Feedback
❓ Frequently Asked Questions
Complete your Finance picture
These tools naturally pair with the Refinance Calculator — use them in order to get a full view.