Should you refinance? Compare your current mortgage to a new rate — monthly PI savings, months to break even on closing costs, and lifetime interest.
Positive lifetime difference means the new loan costs more interest over its term (often because the term is longer). Negative means you pay less interest.
Next money step: cross-check the new payment on the Mortgage Calculator and house fit on Affordability, then shop lenders with your break-even months in hand. We do not sell lender leads yet. As an Amazon Associate, DynDisc earns from qualifying purchases on our picks.
Enter your current balance, rate, and remaining years, then the new rate, new term, and estimated closing costs. The tool amortizes both loans for principal and interest (PI) only — taxes and insurance are not included. You get current monthly PI, new monthly PI, monthly savings, break-even months, and the lifetime interest difference between the two schedules.
Break-even is simple: closing costs ÷ monthly PI savings. If you save $200 a month and pay $6,000 to close, break-even is 30 months. If the new PI is not lower, break-even is never — refinancing for a lower rate alone is not enough when the payment does not drop.
Refinancing is a keep-the-house decision. It tends to win when (1) you will stay past break-even, (2) monthly savings actually recoup fees, and (3) lifetime interest does not blow up because you restarted a long term. Dropping from 6.75% to 5.75% on a large balance can free real cash each month — but rolling fees into a fresh 30-year loan can mean more interest over the full schedule even when the payment looks better.
Watch the term. Refinancing 27 years left into a new 30-year loan stretches payments and often raises total interest. Refinancing into 15 or 20 years may raise the monthly PI while cutting interest hard. Use the lifetime interest line on this page as a second vote next to break-even.
Closing costs here are a single dollar input — appraisal, title, origination, and points lumped together. If you finance costs into the new balance, your true PI rises; this model keeps the balance fixed so you can see the clean rate-and-term effect. Cash-out refinance is not modeled: pulling equity changes the balance and the risk profile.
Also outside scope: PMI removal, ARM resets, credit-score rate tiers, and lender credits. Treat the numbers as an educational PI estimate, then verify quotes with a lender. Pair this page with the mortgage payment calculator and loan payoff calculator when you want payment detail without the refinance frame.
Stay if you will sell before break-even, if savings are tiny relative to fees, or if stretching the term makes lifetime interest worse for no good reason. Refinance if you will keep the home past break-even, the payment drop is real, and interest either falls or the cash-flow trade is worth it for your plan. Re-run the calculator whenever a quote changes the rate, points, or fees — small fee swings move break-even months a lot.