Mortgage Refinance Calculator: Savings and Break-Even Point
Compare the estimated cost of keeping a mortgage with replacing it through a refinance, including closing costs and the time needed to recover them.
Inputs and calculation method
- Current balance, rate, payment, and remaining term
- Proposed refinance rate and term
- Closing costs and points
- Expected time in the home
The tool estimates the old and new amortized payments, compares monthly cash flow, and divides eligible upfront costs by monthly savings for a simple break-even estimate. It also compares remaining total interest.
Core formula: Simple break-even months = refinance closing costs ÷ estimated monthly payment savings.
How to interpret the estimate
A refinance can reduce the payment but increase lifetime interest if the loan term is restarted for many additional years. Compare both monthly and total costs.
Change one assumption at a time to understand which input has the greatest effect. Use exact figures from a lender disclosure, statement, pay record, account terms, or business records whenever possible. Calculator output is rounded and may differ from institution-specific calculations.
How to use this calculator effectively
Use exact figures from a lender or property estimate when available, then build a conservative scenario that allows for rate, tax, insurance, and maintenance uncertainty.
A refinance should be evaluated as a new transaction, not only as a lower payment. Enter lender fees, title and appraisal costs, points, credits, any cash added to the balance, and the time you expect to keep the new loan. A lower payment can come from restarting a longer term even when lifetime borrowing cost increases.
- Step 1: Current balance, rate, payment, and remaining term. Use a value from a current statement, written quote, account record, or documented plan whenever possible.
- Step 2: Proposed refinance rate and term. Use a value from a current statement, written quote, account record, or documented plan whenever possible.
- Step 3: Closing costs and points. Use a value from a current statement, written quote, account record, or documented plan whenever possible.
- Step 4: Expected time in the home. Use a value from a current statement, written quote, account record, or documented plan whenever possible.
What changes the result most
- Rate reduction: the difference between the current and proposed rates affects monthly interest savings.
- Closing costs and points: upfront or financed costs must be recovered before the transaction produces net savings.
- Remaining time in the home or loan: selling or refinancing again before break-even can eliminate the expected benefit.
- New term and balance: extending the payoff date or rolling costs into principal can reduce payment while increasing total interest.
Practical decision guide
Compare the old and new loans over the same ownership horizon. Review monthly cash-flow savings, break-even month, balance at the expected sale date, and total cost through that date. If the purpose is cash flow rather than lifetime savings, label that tradeoff clearly. Use written Loan Estimates with matching assumptions whenever possible.
Questions to ask before relying on the result
- Which input is documented and which one is only an assumption?
- How does the result change under a more conservative rate, cost, payment, or time horizon?
- What cash-flow, risk, tax, legal, or contractual factor is not represented by the formula?
Common mistakes to avoid
- Dividing closing costs by payment savings without considering balance differences or a changed term.
- Ignoring points, prepaid items, and fees added to the new principal.
- Comparing the remaining interest on the old loan with a full new 30-year schedule without using the same horizon.
- Assuming an escrow refund is a permanent refinance saving rather than the return of previously funded money.
Limitations and how to verify the estimate
Actual break-even depends on payment dates, tax treatment, lender credits, appraisal outcomes, insurance, prepayment behavior, and how long the loan remains open.
Recheck the calculation when an input changes and compare the output with the applicable statement, disclosure, contract, plan document, or official source. Do not use a calculator result as a substitute for individualized financial, tax, legal, lending, investment, insurance, payroll, or accounting advice.
Save the date, inputs, and purpose of each scenario. That record makes later comparisons more reliable and helps explain why a result changed. When comparing alternatives, use the same measurement period and cost definitions; otherwise a seemingly better result may come from inconsistent assumptions rather than a genuine financial advantage.
Official references and further reading
- Consumer Financial Protection Bureau: Owning a home — Official tools and explanations for mortgage shopping, loan estimates, closing costs, and homeownership decisions.
Frequently asked questions
What costs should I include?
Include lender fees, appraisal, title charges, recording, points, and other costs that would not otherwise be paid.
Is the break-even calculation enough?
No. Also compare the new payoff date, total interest, cash paid at closing, and how long you expect to keep the loan.
Does cash-out refinancing change the comparison?
Yes. Separate the cost of refinancing the existing balance from the additional amount borrowed.
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Last technical review: June 26, 2026. Methodology is provided for transparency. This calculator is educational and does not provide financial, tax, legal, investment, lending, insurance, or accounting advice. Read the methodology and calculator disclaimer.