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Mortgage Refinance Calculator
Compare current and replacement mortgages by payment, break-even months, total interest and lifetime cost after closing costs and points.
Mortgage Refinance Calculator: Check whether a lower mortgage payment also lowers your total cost. Compare the full remaining term of the current loan against the full term of the new loan, with all fees paid upfront. Runs 100% locally in your browser with zero server file uploads.
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- Home & family tools
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- In your browser
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- Free · no sign-up
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- Ready to use
Runs entirely in your browser
Closing costs and points are paid upfront. Both loans use the same balance and fixed monthly principal-and-interest payments. Taxes, insurance, cash-out, penalties and financed fees are excluded.
- Monthly saving ($)
- -24.13
- Simple break-even (months)
- Not reached during both terms
- Lifetime saving after fees ($)
- 93,725.76
- Upfront costs and points ($)
- 6,500.00
| Loan | Monthly P&I ($) | Total interest ($) | Payments and fees ($) |
|---|---|---|---|
| Current | 1,766.95 | 280,084.40 | 530,084.40 |
| New | 1,791.08 | 179,858.64 | 436,358.64 |
A negative saving means refinancing costs more. Simple break-even divides upfront costs by monthly savings, rounded up; it applies only while both loans would still run. It does not compare equity or sale proceeds. Lifetime savings compare both full remaining terms without discounting future money.
Amortisation and points
OpenStax: loan amortisation: https://openstax.org/books/principles-finance-2e/pages/8-3-loan-amortization explains how regular payments reduce a loan. With monthly rate r and n payments, payment = principal × r / (1 − (1 + r)^−n); at zero interest, divide principal by n.
CFPB: points and lender credits: https://www.consumerfinance.gov/ask-cfpb/how-should-i-use-lender-credits-and-points-also-called-discount-points-en-136/ describes upfront points. This comparison uses balance × points / 100 plus the separate closing-cost amount.
Comparing different terms
Monthly saving is current payment minus new payment. Lifetime saving is current remaining payments minus new payments and upfront fees. Negative values mean refinancing costs more.
No cash-out, financed costs, tax deductions, escrow changes or prepayment penalties are included. A simple payment break-even does not imply that equity is equal at that date.
How to use it
- Enter the current balance, annual rate and months remaining.
- Enter the new rate, term, closing costs and points.
- Compare payment savings, simple break-even and lifetime savings.
Privacy & limitations
All calculations run in your browser. No financial inputs are uploaded.
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Frequently asked questions
How are points counted?
One point is 1% of the loan balance. Enter closing costs excluding points so the fees are not counted twice. All fees are paid upfront.
Why can monthly savings be positive but lifetime savings negative?
A longer new term can lower the payment while adding years of interest. Fees can also outweigh interest savings.
What does break-even mean here?
Upfront costs divided by monthly payment savings, rounded up. It is shown only within the period when both loans would still run. It does not measure equity, discounted cash flow or the proceeds from selling the home.
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