Mortgage Refinance Calculator (USA)
Compare your current mortgage vs a refinance: monthly payment, total interest, and breakeven time — with clear charts and breakdown.
Inputs
How to use
- Enter your current balance, current rate, and months remaining.
- Enter your expected new refinance rate and select a new term.
- Add closing costs and choose whether you pay them upfront or roll them into the loan.
- Choose a comparison horizon (e.g., 10 years) and click Calculate.
Tip: Breakeven is meaningful only if you expect to keep the loan long enough to recover closing costs.
Mortgage refinance in the USA: how to compare real savings
Refinancing a mortgage means replacing your existing home loan with a new one. People refinance to lower the interest rate, change the term length, switch from adjustable to fixed (or the other way around), or tap home equity with a cash-out refinance. The key is that a refinance has tradeoffs: it can reduce your monthly payment, but it also has closing costs and often resets the amortization schedule. A smart comparison looks at both the monthly cash flow and the total interest paid over time.
Start with the numbers you can verify: your current loan balance, your current APR, and how many payments you have left. This calculator estimates your remaining monthly principal-and-interest payment and then compares it to a refinance scenario with a new rate and new term. If you extend the term (for example, going from 20 years remaining back to a 30-year loan), your payment may drop, but you might pay more interest overall. If you shorten the term, your payment can rise while total interest often falls.
Closing costs matter because they are effectively the “price” of the refinance. You might pay them upfront, or you might roll them into the new loan balance. Paying upfront keeps the new principal lower, while rolling costs in increases your interest expense over time. The calculator uses closing costs to compute a simple breakeven time based on monthly savings: if the refinance lowers your payment by $150 and your closing costs are $4,500, breakeven is about 30 months. If the refinance does not reduce your payment (for example, because you shortened the term or rolled in large costs), breakeven may not apply.
Another important factor is your time horizon. Many homeowners refinance and then move or refinance again within a few years. That’s why this calculator lets you compare totals over a set horizon (like 5, 7, or 10 years) instead of only looking at “full term” totals. A refinance can look great on a 30-year total interest basis but still be a poor deal if you sell the home in 2–3 years and never reach breakeven.
Cash-out refinancing changes the math because it increases your principal. The refinance may still lower the rate, but the new loan balance is higher due to the cash you take out. If you are using cash-out to consolidate high-interest debt, compare the refinance outcome to the cost of keeping that debt (and the risk of turning unsecured debt into secured debt). Also remember that taxes, insurance, HOA dues, and escrow requirements can affect your total monthly payment even if principal-and-interest drops.
Use the charts to sanity-check the decision. The cumulative cost line chart shows how payments add up over time, including closing costs when paid upfront. The bar chart compares your monthly payment and interest over the chosen horizon. If the refinance line stays below the current line beyond your expected ownership period, that’s a strong signal that refinancing may save money — assuming you qualify for the quoted rate and terms.