Refinance Calculator

Compare your current loan to a refinanced loan. See monthly savings, total interest savings, and break-even point.

This calculator compares your current loan's fixed payment against a refinanced loan's payment, folding Closing Costs directly into the new loan's balance (line 30, newBalance equals currentBalance plus closingCosts) rather than assuming they are paid out of pocket — so New Payment, New Total Interest, and the resulting savings all already account for a slightly larger new loan than your current balance alone. Break-Even Point is simply Closing Costs divided by Monthly Savings, rounded up to a whole month (line 41), and it returns exactly 0 whenever Monthly Savings is not positive — refinancing to a higher payment never has a break-even point in this calculator's terms. Current Interest Rate dominates Break-Even Point: its ±10% span moves Break-Even Point by a full 100% (versus about 86% for New Interest Rate). At the calculator's own default 30-year New Loan Term, Current Interest Rate also dominates Monthly Savings, moving it by about 85% of Monthly Savings (versus about 73% for New Interest Rate). Neither dominance is because of any special "reference point" role in the formula — the current-loan and new-loan branches (lines 21-27 and 31-37) are mathematically symmetric. Monthly Savings' ranking is simple magnitude: at the calculator's defaults Current Interest Rate (6.5%) is higher than New Interest Rate (5.5%), so a matched ±10% move produces a bigger dollar swing in Current Payment (about $203) than the same move produces in New Payment via New Interest Rate (about $176) — and both dollar swings are measured against the same small Monthly Savings denominator ($240.16 at the defaults), which is what turns an ordinary dollar difference into a large percentage gap. That ranking isn't permanent, though: New Loan Term sits at its own 30-year maximum by default, and shortening it sharply raises New Payment (amortizing the same balance over fewer months costs far more per month) — push New Loan Term down toward its 1-year floor and New Loan Term itself becomes the biggest driver of Monthly Savings instead, ahead of either interest rate. Total Savings, by contrast, has no single clear leader: New Interest Rate, New Loan Term, Current Interest Rate, and Years Remaining all move it by strikingly similar amounts, roughly 400-430% across a ±10% probe. Those percentages look dramatic, but Total Savings is actually NEGATIVE at this calculator's own defaults (about -$14,825 — refinancing loses money at the stated 6.5%-to-5.5% rate move given the $5,000 closing costs and 25-versus-30-year terms), and dividing by that small negative base is what inflates the percentages; it is not evidence that the four inputs are unusually powerful, and "no single clear leader" should be read with that small-denominator caveat in mind rather than as a standalone insight. This calculator does not account for prepayment penalties on the current loan, tax implications, or the possibility that mortgage insurance requirements change along with a new loan-to-value ratio.