About the Refinance Calculator
A refinance calculator helps you decide whether replacing your current mortgage with a new loan saves money. It quantifies the monthly payment reduction, the closing costs, and the break-even point — the number of months you must keep the new loan for the savings to outweigh the upfront cost. Below the break-even, a refinance loses money even at a lower rate.
The break-even rule of thumb
Closing costs on a refinance typically run 2–5% of the loan amount: appraisal, title insurance, origination fees, taxes, recording fees, and possibly discount points. To find the break-even, divide total closing costs by the monthly payment savings. If your closing costs are $6,000 and you save $200/month, your break-even is 30 months — meaning you need to stay in the home (and the new loan) at least 2.5 years to come out ahead.
The longer you plan to stay, the more a refinance helps. If you might sell or refinance again within 1–2 years, the math is much harder to justify; in those cases, a no-closing-cost refinance (where the costs are rolled into a slightly higher rate) can sometimes be the right answer despite the worse-looking rate on paper.
The hidden cost of resetting amortization
Refinancing into a new 30-year loan when you're 7 years into your current 30-year resets your loan to 30 years. Your monthly payment may drop, but you've extended the loan by 7 years — and unless the rate is dramatically lower, you may pay more total interest, just stretched over more years.
Two ways to neutralize this: refinance into a shorter term (say, a 20- or 15-year loan), or refinance into a 30-year and continue making the original higher monthly payment as voluntary extra principal. Both eliminate the "interest stretch" while still capturing the lower rate.
Cash-out refinance: when borrowing against home equity makes sense
A cash-out refinance replaces your current mortgage with a larger one and gives you the difference in cash, secured by the home. At a moderate mortgage rate it's typically the cheapest way to borrow large amounts, especially compared to credit cards or unsecured personal loans.
The trade-off: you're converting unsecured spending or higher-rate debt into a debt that puts the home at risk if you can't pay. Use cash-out refinances for high-return uses (consolidating much higher-rate debt, value-adding home improvements, education, healthcare) — not for vacations, cars, or general lifestyle spending.
Removing PMI as a refi motive
If your home has appreciated meaningfully since purchase, a refinance may push you below the 80% loan-to-value threshold and eliminate PMI even before you would have hit it on the original schedule. On a $400,000 home with 10% down originally, two or three years of price appreciation can be enough to refinance with PMI removed — a savings often worth $150–$300/month on top of any rate improvement.
How it works
- Capture current loan details. Remaining balance, current rate, remaining term, and current monthly P&I.
- Enter new loan terms. Proposed rate, new term, and total closing costs (appraisal, title, origination, taxes, recording, points).
- Compute monthly savings. Difference between current and new monthly P&I. Be consistent: don't compare a 30-year refi against a remaining 22 years on the existing loan without adjusting.
- Calculate break-even. Closing costs ÷ monthly savings = break-even months. Compare to your expected time in the home.
- Sanity-check total interest. Compare the total interest remaining on the current loan to total interest on the new loan over its full term, especially when extending the term.
Worked examples
Rate-and-term refinance: 7.25% → 6%
$280,000 balance, 22 years remaining at 7.25% ($2,047/month). Refinance to a 22-year loan at 6%: new payment ≈ $1,853/month, saving $194/month. Closing costs $5,600. Break-even = 5,600 ÷ 194 ≈ 29 months. If you'll keep the home longer than 2.5 years, the refi pays off.
30-year reset trap
Same $280,000 balance refinanced to a new 30-year at 6%: payment drops to $1,679/month (saving $368). But you've added 8 years; total interest over the new 30-year ≈ $324,000 vs. $260,000 in the remaining 22 years on the old loan — about $64,000 more, despite the lower rate.
Cash-out for high-rate debt consolidation
Original mortgage $200,000 balance at 6.5%. $25,000 in credit-card debt at 22%. Cash-out refi to $225,000 at 6.75% (slightly higher rate due to higher LTV). Monthly mortgage payment rises by ~$170 but credit-card minimums of ~$650/month disappear. Net cash flow improves by ~$480/month.
Frequently asked questions
How much lower does the new rate need to be to refinance?
The old rule was 1 percentage point, but with closing costs varying widely, the better rule is to compute the actual break-even. Even a 0.5-point reduction can pay off if you'll stay in the home 5+ years and closing costs are modest. A 2-point reduction with high closing costs and a planned move next year is still a bad refi.
Should I roll closing costs into the new loan?
Rolling costs in keeps cash in your pocket but means you finance them at the loan's rate over its full term — turning a $5,000 closing cost into perhaps $11,000 over 30 years. Pay closing costs out of pocket if you can; if you can't, consider a no-closing-cost refi (slightly higher rate) instead.
What credit score do I need to refinance?
Most conventional refinance programs require 620+, with the best rates at 740+. FHA streamline refinances can be available with lower scores. Improving a score from 680 to 760 before applying can save 0.25–0.5 points on the rate.
Are there closing costs even on a no-closing-cost refi?
Yes — they're either rolled into the loan balance or paid for via a higher rate (lender credit). They never disappear; they're just made invisible. Compare on total cost of borrowing over your expected ownership horizon, not on the headline closing-cost figure.
Does refinancing hurt my credit?
There's a small, temporary hit from the hard credit pull at application — typically 5–10 points, recovering within a few months. Multiple mortgage inquiries within a 14–45 day window are usually counted as one inquiry by FICO, so you can shop lenders without compounding the damage.
Can I refinance if I'm underwater?
Conventional refinances generally require equity (loan-to-value at or below a threshold, often 97% on rate-and-term refinances). FHA streamline refinances and certain government-backed programs allow refinancing with limited or no equity, but options are narrower and the streamline process has its own restrictions.
Related calculators
Concepts
Sources & methodology
- Consumer Financial Protection Bureau — Should I refinance? — source