A best refinance calculator answers one question first: how many months until closing costs are paid back by a lower payment. Run break-even with your real rate, term, and fees before you lock.
Free refinance calculator: compare monthly payment, break-even on closing costs, and total interest vs your current mortgage.
Practical tip Start with round numbers from your bank or contract. You can refine decimals after the first pass.
What to enter
Have these handy before you start. Names vary by tool, but the ideas are the same.
Current loan balance, rate, and remaining term
New rate, term, and estimated closing costs
How long you expect to keep the loan or stay in the home
Extra principal payments you plan after refinancing
If break-even exceeds your stay horizon, refinancing may not pay.
Free calculator Use the mortgage refinance calculator for break-even months, monthly savings, and lifetime interest after closing costs.
Worked example (illustrative)
You owe $320,000 at 6.75% with 27 years left. A refi offer is 5.75% for 30 years with $4,200 in closing costs. Monthly payment might fall from about $2,080 to $1,870—a $210 cushion. Break-even on fees is roughly 20 months ($4,200 ÷ $210). If you sell the home in 3 years, refi can still win on payment savings, but resetting to 30 years adds total interest versus keeping the old amortization schedule. Enter the same numbers in the refinance savings calculator and try a 20-year term to see payment vs total cost—not a Loan Estimate from your lender.
Common search questions
Best refinance calculator — break-even months after closing costs vs monthly payment savings.
Open the tool when you already have a quote, a deadline, or a what-if and need a clear number for loans.
Situations people use it for
Mortgage rate dropped and you want break-even months after closing costs
Comparing 30-year refi vs keeping a 15-year paydown pace
Deciding whether to roll closing costs into the new loan balance
How to read the result
Treat the output as a structured estimate. Small input changes should move the result in a direction that makes sense.
Run a conservative case first. If it still works, you have margin.
Change one field at a time so you know what actually moved the number.
Save the scenario with a name you will recognize later ("2027 refi", "15-year plan").
This model assumes: Free refinance calculator: compare monthly payment, break-even on closing costs, and total interest vs your current mortgage.
Common slip-ups
Comparing APR quotes with different fee structures
Looking only at monthly payment, not total interest
Assuming extra payments apply the way your bank applies them
Try it with your numbers
Open the Best Refinance calculator, enter your case, and keep a screenshot or PDF if you will revisit the decision. Everything runs in your browser; your inputs are not sent to our servers for the math.