Mortgage Refinance Calculator
Compare your current mortgage with a proposed refinance, including costs, cash-out, break-even time, and a chosen holding period.
How the refinance comparison works
The calculator amortizes the current balance over its remaining term and separately amortizes the proposed new loan. The new principal includes cash-out and, when selected, financed closing costs. It compares payments, interest, remaining balances, and equivalent cash flows.
M = P × r(1 + r)n ÷ [(1 + r)n − 1]
Break-even estimate
When the new payment is lower, the simple break-even time equals refinance closing costs divided by monthly payment savings. It answers how long payment savings take to recover the transaction cost. If the proposed payment is not lower, there is no payment-based break-even even though shortening the term could still reduce total interest.
Holding-period comparison
At the selected horizon, each option includes payments made plus the remaining loan balance. The refinance side also includes upfront costs and subtracts cash received at closing. This avoids treating cash-out proceeds as savings or ignoring the balance still owed.
Full-term savings
Net full-term savings compares all remaining payments on the current loan with all payments on the new loan, plus any upfront costs and minus cash-out proceeds. A longer replacement term can lower the monthly payment while increasing total interest, so review both results.
Important limits
The estimate assumes fixed rates, monthly payments, no prepayment penalty, and no change in taxes, insurance, HOA, or mortgage insurance. It excludes appraisal timing, points not entered in closing costs, tax effects, adjustable rates, and lender qualification. Obtain an official loan estimate before deciding.
Related calculators
- Mortgage Payoff Calculator — compare extra payments without refinancing.
- Mortgage Affordability Calculator — estimate a purchase budget from income and debts.
- Mortgage Calculator — estimate a payment from a purchase price.
Alternative borrowing: estimate a fixed second-lien payment, available equity, and combined LTV without replacing the first mortgage using the Home Equity Loan Calculator.
Keep the first mortgage: estimate a revolving home-equity line with draw-period and repayment-period payments using the HELOC Calculator.