CalcKitHow to Use the Refinance Calculator
Refinancing means replacing your current mortgage with a new one — usually to grab a lower interest rate. It can save thousands, but closing costs (fees, typically 2–5% of the loan) mean it only pays off if you stay long enough. This calculator answers the two questions that matter: how much do I save monthly? and when do I break even?
Enter your current balance, rate and years left, plus the new rate, term and closing costs. Press Compare Refinance to see both payments side by side, your monthly savings, the break-even point (closing costs ÷ monthly savings), and total interest under each option.
The classic rule: refinancing makes sense when you can drop your rate by about 0.75–1% and you'll stay past break-even. Watch the term trap — refinancing 25 years left into a new 30-year loan lowers the payment but can increase total interest. Compare the "interest: stay vs refinance" row, not just the monthly payment.
Also consider a shorter term: refinancing into a 15-year loan often has the lowest rates and builds equity fast, if the higher payment fits your budget. For purchase maths, see our Mortgage Calculator.