Last updated: March 2026
What Is a Mortgage Refinance Calculator?
A mortgage refinance calculator helps you determine whether replacing your current mortgage with a new one will save you money. It compares your existing loan terms against proposed new terms and calculates the monthly payment difference, total interest savings, and the critical break-even point — the moment when your accumulated savings exceed the cost of refinancing.
Refinancing is one of the most powerful financial moves a homeowner can make, but only when the numbers work in your favor. According to Freddie Mac, borrowers who refinanced in recent years saved an average of $2,800 per year on their mortgage payments. However, refinancing comes with closing costs typically ranging from 2% to 5% of the loan amount, so timing and math matter enormously.
How to Use This Calculator
Start by entering your current loan details: remaining balance, interest rate, and remaining term. The calculator automatically computes your current monthly payment. Then enter the new loan terms you are considering: interest rate, loan term, and estimated closing costs. Results update in real-time as you adjust any input — no button to click, no waiting.
The results dashboard shows your monthly savings, total interest comparison, and break-even timeline at a glance. Scroll down to the amortization comparison chart to visualize how both loans pay down over time, and use the detailed amortization table to see month-by-month numbers for both scenarios.
Understanding Break-Even Analysis
The break-even point is the single most important number in any refinance decision. It tells you how long you need to keep the new mortgage before the monthly savings offset the upfront closing costs. If you plan to sell your home or refinance again before reaching break-even, you will lose money on the transaction.
Financial advisors generally consider a break-even under 3 years to be excellent, 3 to 5 years acceptable, and over 5 years a reason for caution. This calculator color-codes the break-even result so you can instantly see where your scenario falls. Keep in mind that a cash-out refinance adds to your loan balance and extends the break-even period, since you are borrowing more than your current balance.
Beyond break-even, consider the total cost of both paths. Sometimes a lower monthly payment comes with a longer term that results in more total interest paid. This calculator shows both perspectives so you can make a fully informed decision.
Frequently Asked Questions
When does it make sense to refinance my mortgage?
Refinancing typically makes sense when you can lower your rate by at least 0.5-0.75%, plan to stay in the home past the break-even point, and the closing costs are reasonable relative to your monthly savings. A shorter break-even period (under 3 years) is a strong indicator that refinancing is worthwhile.
What is the break-even point on a refinance?
The break-even point is the number of months it takes for your monthly payment savings to recoup the closing costs of the refinance. For example, if closing costs are $6,000 and you save $200/month, your break-even is 30 months. If you sell or refinance again before reaching break-even, you lose money on the deal.
How much do refinance closing costs typically run?
Refinance closing costs typically range from 2% to 5% of the loan amount. On a $300,000 loan, expect $6,000 to $15,000. Costs include appraisal ($300-$600), title insurance ($500-$1,500), origination fees (0.5-1% of loan), and various administrative fees. Some lenders offer no-closing-cost refinances, but they charge a higher interest rate to compensate.
Should I refinance from an ARM to a fixed-rate mortgage?
If your ARM adjustment period is approaching and rates have risen, locking in a fixed rate provides payment certainty. Even if the fixed rate is slightly higher than your current ARM rate, the protection against future rate increases can be valuable. Consider how long you plan to stay in the home and your risk tolerance for payment fluctuations.
How does my credit score affect refinance rates?
Your credit score significantly impacts the rate you qualify for. Borrowers with scores above 760 typically get the best rates. Each 20-point drop can add 0.125-0.25% to your rate. Before applying, check your credit report for errors, pay down credit card balances below 30% utilization, and avoid opening new accounts. Even a small rate improvement can save thousands over the life of the loan.