What the Refinance Calculator Compares
Use the calculator to compare a current mortgage with a proposed fixed-rate refinance. Review the monthly principal-and-interest payment, cash to close, total payment-and-fee cost over the planned holding period, net savings or cost, break-even month, total interest, and annual amortization results.
Enter the Mortgage and Refinance Details
- Enter the current mortgage's Remaining balance ($), Current annual rate (%), and Remaining term (years). Leave Current monthly P&I ($, optional) blank to calculate it, or enter the payment you use.
- Enter the proposed refinance's New annual rate (%), New loan term (years), Closing costs ($), Points (optional), and Cash-out amount ($, optional).
- Check Roll closing costs & points into the new loan to add those fees to the new balance instead of paying them upfront.
- Optionally enter Monthly property taxes ($, optional), Monthly homeowners insurance ($, optional), and Planned holding period (years, optional). The holding period must be greater than 0 and no more than 100 years; if blank, it defaults to the new loan term.
- Click Calculate. Use Reset to clear the form and start again.
Review Payments, Costs, and Break-Even
The payment formula treats both loans as fixed-rate loans:
r = Annual rate / 100 / 12
Payment = Principal x r / (1 - (1 + r)^-n), where n is the term in months. Points cost is calculated from the current balance plus cash-out. Monthly property taxes and homeowners insurance are added equally to both options, so they appear in the full PITI comparison but do not change principal-and-interest break-even savings.
The displayed break-even value is calculated as:
Break-even month = (Closing costs + Points cost) / (Current payment - New payment)
This calculation uses total closing costs and points whenever the new payment is lower, including when Roll closing costs & points into the new loan is checked. Treat that figure as a limitation of the calculator: it does not represent a separate recovery calculation for upfront cash when fees are rolled into the balance. If the new payment is not lower, no break-even month is shown.
Holding-period totals are calculated payments plus fees from the values you enter. They are not a complete payoff-balance, home-equity, escrow, or tax analysis.
Use the Holding-Period and Amortization Results
Payment totals are capped at each loan's term. The annual amortization table shows end-of-year balances and cumulative interest. When the holding period includes a decimal year, the highlighted row uses the rounded whole year, so it may be an approximate reference rather than the exact holding-period month.
- Rolling costs into the new loan increases the new balance, payment, and total interest, while reducing cash needed at closing to 0 before cash-out.
- Leaving taxes or insurance blank treats each value as 0.
- The calculator does not model adjustable rates, PMI, lender credits, escrow refunds, appraisal outcomes, or qualification requirements.
Validation, Assumptions, and Privacy
Required numeric values must be valid. Rates must be between 0 and 100, loan terms must be greater than 0 and no more than 100 years, points must be between 0 and 10, and entered costs, cash-out, taxes, and insurance cannot be negative. An entered current payment must cover the first month's interest. The planned holding period must be greater than 0 and no more than 100 years.
Calculations run in the browser, and script.js does not send the values entered into the calculator to a server. This describes the calculator logic only; the page also contains separate site features such as analytics and a subscription form. Results are mathematical estimates, not financial, tax, or lending advice.
Copy or Download the Result
After calculating, use Copy result to copy the generated plain-text result, or use Download result (.txt) to save it. The text includes the main entered loan details, new-loan figures, payment difference, cash to close, break-even value, full-term interest, holding-period savings, and annual balance-and-interest rows. It does not include the on-page formula, assumptions table, taxes and insurance fields, PITI rows, holding-period interest rows, or the complete comparison table.
Frequently Asked Questions
How is the break-even month for a refinance calculated?
Break-even month = total closing costs and points divided by monthly principal-and-interest savings. The current script uses those total fees even when Roll closing costs & points into the new loan is checked, so the displayed value should not be treated as a separate upfront-cost recovery calculation. If the new payment is not lower, a break-even month is not shown.
What counts as cash to close?
Cash to close is upfront closing costs and points, minus cash-out. When costs are rolled into the new loan, the upfront fee amount is 0 before cash-out, so the result can be negative when cash-out exceeds it.
How does rolling closing costs into the loan affect the comparison?
The calculator adds closing costs and points to the new loan amount. This can increase the new payment and total interest while reducing cash needed at closing to 0 before cash-out. The break-even display still uses total fees, as noted above.
Why are property taxes and insurance included if they do not change with a refinance?
They are added equally to both principal-and-interest payments so the result can show a full PITI payment. Because the same amounts are added to both options, they do not change the principal-and-interest break-even savings.
Does this tool fetch live mortgage rates or give lending advice?
No. It uses the figures you enter and fixed-rate assumptions. It does not fetch live rates, credit records, or lender data, and it does not provide personalized financial, tax, or lending advice. It also does not calculate a complete home-equity, payoff-balance, escrow, or tax analysis.