The Mortgage Refinance Calculator helps homeowners decide whether refinancing makes financial sense by computing monthly savings, total interest reduction, and the break-even point : the month when cumulative savings exceed closing costs. Refinancing can save thousands over the life of a loan, but only if you remain in the home long enough to recoup the upfront costs. The core refinancing math is straightforward: if your new rate produces a lower monthly payment, closing costs (typically 2–5% of the loan amount) will be recovered over time. Divide total closing costs by the monthly savings to find the break-even month. If you plan to sell before that month, refinancing likely isn't worth it. If you'll stay well beyond it, refinancing makes clear financial sense. However, the break-even analysis alone isn't the complete picture. Refinancing to a new 30-year term resets the amortization clock : even at a lower rate, you may pay more total interest than if you'd continued on your existing loan. This calculator also shows total interest under both scenarios so you can weigh the monthly cash flow benefit against the lifetime interest cost. Additional considerations include: whether you plan to switch from an adjustable-rate mortgage (ARM) to a fixed rate for payment certainty; whether you want to shorten your term from 30 to 15 years; and whether a no-closing-cost refinance (slightly higher rate) might be preferable given your timeline.
Enter your details and click Calculate to see results.
Saved Presets is a Supporter feature.
Tool History is a Supporter feature.
Tool Notes is a Supporter feature.
Input your remaining loan balance, current interest rate, and remaining term. This is your baseline for comparison.
Input the new interest rate you've been quoted, the new loan term (e.g., 30 years), and your estimated closing costs. The calculator uses 2–5% of the new loan as the default closing cost estimate if you don't have an exact figure.
The calculator shows the break-even month, your monthly payment reduction, and how much you'll save in total interest if you keep the new loan to term.
Adjust the new term (15 vs 30 years) or test a no-closing-cost option to see which refinance structure best fits your timeline and financial goals.
Break-Even Months = Total Closing Costs / Monthly Payment Savings. If closing costs are $6,000 and the new payment is $150/month lower: break-even = 40 months (about 3.3 years). If you plan to stay 5+ years, the refinance saves money. If you plan to move in 2 years, it doesn't.
Monthly Savings = Old Payment − New Payment. Old payment uses current balance, current rate, and remaining term. New payment uses current balance, new rate, and new term (typically a fresh 30 years). A drop from 7.5% to 6.5% on a $350,000 balance saves approximately $220–$230 per month.
The calculator computes total remaining interest on the old loan (remaining payments × old payment − remaining principal) and compares it to total interest on the new loan (new payments × new payment − new principal). Resetting to a 30-year term at a lower rate often produces more total interest than finishing the existing loan, despite the lower monthly payment.
A no-closing-cost refinance charges a slightly higher rate (typically 0.125–0.25% higher) in exchange for lender credits that cover closing costs. The monthly savings are smaller, but break-even is immediate. This option is best for homeowners planning to move or refinance again within 3–5 years.
The old rule of thumb was refinancing only when rates drop 1% or more. Today, even a 0.5% drop can justify refinancing if your loan balance is large and you plan to stay long-term. The break-even calculation is more accurate than any rule of thumb. always compute the specific months-to-recoup-costs for your situation.
