The two numbers most refinance calculators skip
A lower interest rate looks like an easy win, but a refinance has a cost to overcome and a hidden tradeoff to watch. The cost is your closing fees; the tradeoff is the new term. Get both right and the decision is clear — ignore them and a “better” rate can quietly cost you more.
The break-even formula
Break-even (months) = closing costs ÷ monthly savings
Each monthly payment uses the standard amortization formula M = P · r(1 + r)n ÷ ((1 + r)n − 1), whereP is the balance, r is the monthly rate, andn the number of payments. Compare the two payments to get your monthly savings, then divide the closing costs by it to find how long until the refinance pays for itself.
What makes this calculator different
- A real break-even point. We fold in your closing costs and tell you exactly how many months of lower payments it takes to recoup them — the number that decides whether a refinance is worth it.
- Honest total-interest comparison. A lower payment can hide more interest over a longer term. We show current vs. new total interest side by side so you see the real lifetime cost.
- Roll costs in, or pay cash. Toggle whether closing costs are financed into the new balance and watch how it changes the payment and the total.
- A clear verdict. Worthwhile, marginal, or a higher payment — the calculator says which, instead of leaving you to guess.
Frequently asked questions
What is the break-even point on a refinance?+
Refinancing isn’t free — you pay closing costs up front (or finance them). The break-even point is how many months of your new, lower payment it takes for the cumulative savings to equal those closing costs. If your costs are $6,000 and you save $300 a month, you break even in 20 months. Before break-even you’re behind; after it, the savings are real money in your pocket. If you plan to sell or refinance again before break-even, the deal likely costs you more than it saves.
What closing costs come with a refinance?+
A refinance is a brand-new loan, so it carries many of the same fees as the original mortgage: lender origination or points, an appraisal, title search and title insurance, recording fees, and sometimes prepaid interest or escrow. These typically run 2–5% of the loan amount. Enter your quoted total in the calculator — break-even is meaningless without it, which is exactly why a lot of refi calculators leave it out.
Why can a lower monthly payment cost me more in the long run?+
This is the term-reset trap. If you have 24 years left and refinance into a fresh 30-year loan, the lower rate cuts your payment partly because you’ve stretched the balance over six extra years. More years of interest can outweigh the lower rate, so you save monthly but pay more in total interest over the life of the loan. This calculator shows total interest for both loans side by side so you can see the tradeoff — and you can match the new term to the years you have left to make a fair comparison.
When does refinancing actually make sense?+
Generally when the new rate is meaningfully lower than your current one, you’ll keep the loan well past the break-even point, and the refinance doesn’t balloon your total interest (or you’re deliberately shortening the term). It can also make sense to drop mortgage insurance, switch from an adjustable to a fixed rate, or pull out equity. Use the monthly savings, break-even, and total-interest figures together — no single number tells the whole story.
Should I roll the closing costs into the new loan?+
Rolling costs into the loan means no cash out of pocket today, but you finance those costs at the new rate for the full term, so you pay interest on them and your payment is slightly higher. Paying cash up front keeps the principal — and the interest you pay on it — lower. Toggle the option in the calculator to compare both; rolling in is convenient but rarely the cheaper choice over the life of the loan.
Disclaimer: This calculator is for educational purposes only. It assumes fixed rates and a fully-amortizing loan, and ignores taxes, insurance, and any prepayment penalty on your current loan. Actual rates, fees, and terms vary by lender and credit profile. It is not financial or lending advice.