Refinance Calculator
Calculate current and refinanced monthly payments, monthly savings, break-even period, total interest, and net savings based on loan balances, rates, terms, and closing costs. Refinance Calculator helps homeowners and borrowers evaluate refinancing opportunities and determine whether a new loan can reduce borrowing costs.
Highlights
- Compare your current and refinanced monthly mortgage payments.
- Estimate potential monthly payment savings after refinancing.
- Calculate how long it takes to recover closing costs.
- Compare total interest and overall payments between loan options.
- Determine gross and net savings from refinancing.
Table of Contents
How Refinance Calculator Works?
The Refinance Calculator compares the remaining cost of an existing loan with the projected cost of a new loan. It uses the current loan balance, annual interest rates, remaining term, new term, and refinance closing costs. The calculation assumes a fixed-rate, fully amortizing loan with equal monthly principal-and-interest payments.
First, each annual interest rate is expressed as a monthly rate for the payment calculation:
For either loan, the estimated monthly payment is calculated using the standard amortization formula:
Here, M is the monthly payment, P is the loan balance, r is the monthly interest rate, and n is the number of remaining or new loan months. The calculator applies this formula separately to the current loan and the refinanced loan.
| Output | Calculation |
|---|---|
| Current Monthly Payment | Amortized payment using the current balance, current rate, and remaining term. |
| New Monthly Payment | Amortized payment using the current balance, new rate, and new loan term. |
| Monthly Payment Savings | Current monthly payment minus new monthly payment. |
| Current Total Payments | Current monthly payment multiplied by the remaining term. |
| New Total Payments | New monthly payment multiplied by the new loan term. |
| Current or New Total Interest | Total payments minus the loan balance. |
| Gross Interest Savings | Current total interest minus new total interest. |
| Net Refinance Savings | Gross interest savings minus refinance closing costs. |
The break-even period estimates how long monthly payment savings take to recover the closing costs:
A shorter break-even period generally indicates that the refinance costs may be recovered sooner. If the new payment is not lower than the current payment, payment-based savings may be zero or negative, making a conventional break-even comparison unavailable or unfavorable.
Practical Use Cases
Homeowners with a higher-rate mortgage can compare their existing payment with a proposed lower-rate loan to estimate monthly cash-flow improvement, total interest reduction, and the number of months needed to recover closing costs.
Borrowers considering a shorter loan term can test whether a new term changes the monthly payment substantially while reducing total interest over the life of the refinanced loan.
Homeowners planning to move can use the break-even period to assess whether they are likely to remain in the property long enough for the monthly savings to offset refinance closing costs.
Financial counselors and mortgage advisers can compare multiple rate, term, balance, and cost scenarios to explain the difference between lower monthly payments, lower total interest, and positive net refinance savings.
Real estate investors can estimate how refinancing may affect property-level cash flow and evaluate whether the projected payment reduction justifies the upfront refinance expenses.
Accuracy and Limitations
The calculator accurately applies standard fixed-rate amortization formulas to the entered balance, annual rates, loan terms, and closing costs, with rates applied as monthly interest rates and payments rounded for display. It estimates principal-and-interest payments only; property taxes, homeowners insurance, mortgage insurance, escrow changes, lender credits, points, prepayment penalties, variable-rate adjustments, and other unentered fees are excluded. The refinance comparison treats the new loan balance as equal to the entered current loan balance and treats closing costs as a separate expense rather than adding them to the new principal. Break-even timing is a simple closing-cost-divided-by-monthly-savings estimate and does not account for investment returns, tax effects, discounting, or the timing of interest and principal reduction.
Quick Examples
Example #1: Standard Rate Reduction
Evaluate the savings from refinancing a remaining mortgage balance at a lower interest rate with moderate closing costs.
Example #2: High-Balance Refinance
Compare refinancing outcomes for a larger mortgage balance with a substantial interest-rate improvement and higher closing costs.
Example #3: Short-Term Refinance
Assess whether refinancing into a shorter loan term produces meaningful interest savings despite potentially higher monthly payments.
