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What this refinance savings calculator answers
Refinancing replaces your current mortgage (or any installment loan) with a new one — usually with a lower rate, a different term, or both. It almost always involves closing costs, which means refinancing only makes sense if your monthly savings recoup those costs comfortably before you sell the home or pay off the loan. This refinance savings calculator answers the only three questions that matter:
- Monthly savings — what the new payment is vs the current one.
- Break-even months — how many months of savings repay your closing costs.
- Lifetime savings — total interest saved across the new loan, net of fees.
The verdict box turns into a green “refinance pays off” or amber “think twice” based on whether you save money over the new loan's life. The framework matches the CFPB's official refinance checklist.
How to use this refinance savings calculator
- Enter your current loan details: remaining balance, current rate, and months remaining (not original term).
- Enter the new offer: the rate from a written Loan Estimate, plus the proposed term in months. A 30-year refinance is 360.
- Enter realistic closing costs. U.S. refis typically run 2–5% of the loan; ask your lender for a Loan Estimate that itemizes them.
- Read the verdict. Green = refinance pays for itself within the new loan's life. Amber = the math is tighter than it looks.
- Stress test it. Try a slightly worse rate (+0.25%) or higher closing cost (+$1,000) to see how robust the savings are.
Worked example: refinancing $280,000 from 7.25% to 5.75%
Suppose three years ago you took a 30-year, $300,000 mortgage at 7.25%. Your remaining balance is ~$280,000 with 324 months (27 years) left. A new lender offers a 30-year refi at 5.75% with $4,500 in closing costs.
- Current payment ≈ $2,047/month
- New payment ≈ $1,634/month
- Monthly savings ≈ $413
- Break-even ≈
$4,500 ÷ $413 ≈ 11 months - If you keep the loan 10 more years (a typical owner horizon), lifetime savings ≈ $45,000+
That's a clear win. But notice the new term is 30 years — you've added 3 years of mortgage life back on. If you instead refinance into a 27-year term to keep the same payoff date, the new payment is roughly $1,720/month. Lifetime savings drop to ~$32,000 but you stay on schedule. The calculator's lifetime savings number bakes in this trade-off using the new loan's term.
Understanding the break-even formula
Break-even months = Total closing costs ÷ Monthly savings
That single line is the most important rule of refinancing. If your break-even is shorter than the time you plan to keep the home, refinancing wins. If it's longer, refinancing loses — even if the new rate is enticingly lower. Common scenarios:
| Closing costs | Monthly savings | Break-even | Verdict if you stay 7+ years |
|---|---|---|---|
| $3,000 | $200 | 15 months | Strong yes |
| $5,000 | $150 | 33 months | Yes |
| $6,500 | $100 | 65 months | Borderline |
| $8,000 | $70 | 114 months | Probably no |
The hidden cost of restarting the term
Most refinances reset the amortization clock to a new 15- or 30-year term. That's why the monthly savings can look great while the lifetime savings shrink — you've added years of interest, even at a lower rate. To avoid this trap:
- Match your remaining term, not the headline 30-year. If you have 22 years left, refinance into a 22-year (or close) term.
- Or refinance to 30 years and pay extra principal voluntarily equal to the old term's payoff schedule.
- Compare lifetime payments, not just rates. Total repayment over the full term is the only number that captures the trade-off.
Rate-drop thresholds: when refinancing usually wins
A common rule of thumb says refinance only when the new rate is at least 0.5–1% lower than the old rate. The reality depends entirely on your closing costs and remaining balance:
| Rate drop | Closing costs assumption | Typical break-even on $280k loan |
|---|---|---|
| 0.50% | $4,500 | ~30–40 months |
| 1.00% | $4,500 | ~14–22 months |
| 1.50% | $4,500 | ~9–13 months |
| 2.00% | $4,500 | ~6–9 months |
Alternatives to refinancing
- Loan recast. Pay a large lump sum to principal, then ask the lender to re-amortize. Some lenders charge $250–$500 instead of full closing costs.
- Loan modification. Negotiated with your existing lender, often used in financial hardship rather than rate-shopping.
- HELOC or home equity loan. Useful if you need cash, but rarely beats a true refi for replacing the primary mortgage.
- Extra principal payments. Free, immediate, no closing costs. The cheapest way to cut lifetime interest if you don't qualify for a meaningfully lower rate.
Common refinance mistakes
- Comparing rates without comparing APRs. A 5.50% rate with 2 points isn't always cheaper than a 5.75% rate with no points.
- Rolling closing costs into the loan without doing the math. You'll pay interest on those costs for 30 years.
- Restarting a 30-year term in year 25. The lower payment is real; the lifetime cost is not.
- Ignoring break-even relative to your move horizon. If you sell in 3 years and break-even is 4, you've lost.
- Skipping the rate-shopping window. FICO counts multiple mortgage inquiries inside a 14–45 day window as one. Use that.
Read the deeper refinance guide
Full case studies on when refinancing pays off and when it quietly costs you more.
Frequently asked questions
When does refinancing make sense?
When the monthly savings repay the closing costs comfortably before you plan to sell or pay off the loan, and the new rate is at least 0.5–1% lower than your current rate.
What is the refinance break-even point?
Break-even = total closing costs ÷ monthly savings. After that month, every dollar of savings is yours.
Should I roll closing costs into the new loan?
You can, but you'll pay interest on those costs over the entire term. Paying upfront usually wins long term unless cash is tight.
Does extending to 30 years actually save money?
It lowers the monthly payment but typically increases lifetime interest. The lifetime savings number above accounts for this.
Is a 1% rate drop worth refinancing?
Often yes — on a $300,000 mortgage, a 1% drop typically saves $150–$250/month and repays $4,500 closing costs in 18–30 months.
How long does a refinance take to close?
30–45 days for most U.S. refis. Streamline refis (FHA/VA/USDA) can be faster.
Will refinancing hurt my credit score?
The hard inquiry typically drops your FICO 5–10 points and recovers in a few months. Multiple lender inquiries inside 14–45 days count as one.
Can I refinance more than once?
Yes. Each refinance has its own break-even, so always rerun the calculator.
Are there alternatives to refinancing?
Loan recast, modification, HELOCs, or simply paying extra principal are common alternatives with very different cost profiles.
How accurate is this refinance savings calculator?
The math is precise for the inputs you enter. Real lender disclosures may vary based on points or escrow timing. Compare offers by APR.
Sources & further reading. CFPB Refinance Guide · Freddie Mac PMMS via FRED · Internal: When refinancing makes sense, Understanding amortization, U.S. mortgage calculator.