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Mortgage Refinance Calculator Guide

A mortgage refinance calculator determines whether replacing your current loan with a new one at different terms will save you money, factoring in closing costs and break-even timing.


What Is Mortgage Refinancing?

Refinancing replaces your existing mortgage with a new loan, typically to get a lower interest rate, change the loan term, switch from an ARM to a fixed rate, or access home equity through a cash-out refinance. The calculator helps you determine if the savings justify the costs.

Key Inputs

Current Loan Details

Your remaining balance, current interest rate, remaining term, and monthly payment. These establish your baseline costs for comparison.

New Loan Terms

The proposed interest rate, loan term, and any points you would pay to buy down the rate. Even a 0.5% rate reduction on a large balance can yield significant savings.

Closing Costs

Refinancing typically costs 2–5% of the loan amount. This includes appraisal fees, title insurance, origination fees, and recording fees. These costs are critical to the break-even calculation.

Understanding Break-Even Point

The break-even point is when your cumulative monthly savings equal the closing costs. If refinancing saves you $200/month and costs $6,000, you break even at 30 months. If you plan to move before that, refinancing may not make financial sense.

When to Refinance

Consider refinancing when current rates are at least 0.75–1% lower than your existing rate, you plan to stay in the home past the break-even point, your credit score has improved significantly since the original loan, or you want to eliminate private mortgage insurance (PMI) by converting equity.