Last Updated: February 2026
Home Refinance Calculator —
Evaluating the True Cost and Benefit of Refinancing
Refinancing replaces your existing mortgage with a new loan, often at a lower rate or different term. Before committing, it is essential to understand not just the monthly savings but the full cost picture — including closing expenses, the amortization reset, and how long you need to stay for the numbers to work in your favor.
What is mortgage refinancing?
Mortgage refinancing is the process of replacing your current home loan with a new one — typically to obtain a lower interest rate, change the loan term, switch from an adjustable to a fixed rate, or access home equity. The new loan pays off the old one, and you begin making payments on the new terms. Every refinance involves closing costs and resets your amortization schedule from the beginning.
Your Current Loan
New Refinance Options
Monthly Savings (with points)
Lower monthly payment
Break-Even (with points)
Time to recover $4,820 in upfront costs.
5-Year Net Benefit (with points)
(Savings × 60) − upfront. Upfront may be negative with lender credits.
Payment Comparison
Switch views to reduce “empty header” feeling and make the chart work harder.
Points scenario comparison
What Does Refinancing Actually Do?
At its core, refinancing is a loan substitution. Your existing mortgage — with its current balance, interest rate, and remaining term — is replaced by a brand-new loan. The proceeds from the new loan pay off the old one immediately, and you begin making payments on the new terms starting the following month. From a legal and financial standpoint, the old loan no longer exists.
What changes as a result depends on how the new loan is structured. If you refinance to a lower interest rate with the same remaining term, your monthly payment decreases and you pay less interest over the remaining life of the loan. If you refinance to a longer term — say, restarting a 30-year clock after 10 years of payments — your monthly payment may drop significantly, but you extend the repayment timeline and often pay more total interest even at a lower rate. If you shorten the term, payments rise but you eliminate years of interest charges.
Amortization Resets to Month One
Every refinance restarts the amortization schedule. The new loan begins with the same front-loaded interest structure as any new mortgage — early payments are again dominated by interest rather than principal reduction. If you are 10 or 15 years into an existing loan, this reset has significant implications for your long-term interest cost.
Closing Costs Are a Real Expense
Refinancing is not free. Lender origination fees, title insurance, appraisal, recording fees, and other charges typically total 2–5% of the new loan balance. On a $380,000 loan, that is $7,600–$19,000 out of pocket or rolled into the loan balance. These costs must be recovered through monthly savings before the refinance produces any net financial benefit.
Rate Changes Shift the Entire Payment Curve
Because the amortization formula compounds interest monthly over hundreds of payments, even a 0.5% change in rate produces a meaningful difference. On a $380,000 loan, the difference between 6.75% and 5.75% is approximately $230–$270 per month. Over 10 years, that is $27,600–$32,400 in aggregate savings before accounting for the cost of the refinance itself.
Term Changes Affect Total Interest Paid
Extending the loan term reduces the monthly payment by spreading the same balance over more months, but the interest meter runs longer. Shortening the term does the opposite: higher monthly payments but a dramatically lower total interest cost. Refinancing into a 15-year loan from a 30-year loan, for instance, can reduce total interest paid by 40–60% compared to the original schedule, at the cost of higher monthly cash outflow.
It is also possible to roll closing costs into the new loan balance rather than paying them upfront. This preserves cash but increases the principal you are borrowing and, therefore, the total interest you pay. A $380,000 loan with $8,000 in closing costs rolled in becomes a $388,000 loan — and that additional $8,000 accrues interest over the life of the new term, making the effective cost of refinancing higher than the nominal closing cost figure suggests.
Understanding these mechanics matters because the decision to refinance is not purely about the new monthly payment. It is about the net financial outcome over your actual time horizon — which depends on how long you stay, what you do with the monthly savings, whether you plan to refinance again, and how the amortization reset interacts with your equity position. The worked example in Section 3 quantifies all of these factors with real numbers.
How This Refinance Calculator Works
A rigorous refinance calculator does not simply show you your new monthly payment. It compares two distinct financial trajectories: the path you are currently on with your existing loan, and the path you would take with the new loan. The net difference between these two paths, adjusted for closing costs and the time value of your savings, produces the break-even point and long-term outcome.
The Amortization Formula
Both the current loan payment and the proposed new loan payment are derived from the standard mortgage amortization formula. For a full explanation of how this formula works and what each variable represents, see our dedicated mortgage amortization guide. The formula is:
- P — The loan principal. For a refinance, this is the current remaining balance (plus any closing costs rolled in, if applicable).
- r — The monthly interest rate (new annual rate ÷ 12).
- n — The total number of monthly payments in the new loan term (years × 12).
The difference between the old monthly payment and the new monthly payment is the gross monthly savings — before accounting for closing costs and the amortization reset effect.
Remaining Loan Balance
The remaining balance of your current loan is the principal amount the new loan must pay off. It is not the same as your original loan amount — it has been reduced by every principal payment made since origination. After 5 years of payments on a 30-year $400,000 loan at 6.5%, the remaining balance is approximately $375,000, not $400,000. The calculator uses this actual remaining balance, not the original loan amount, to ensure accuracy.
You can find your exact remaining balance on your most recent mortgage statement. If closing costs are rolled into the new loan, the new principal becomes the remaining balance plus those costs.
How do you calculate the refinance break-even point?
The break-even point is the number of months it takes for cumulative monthly savings to equal the total closing costs of the refinance:
If closing costs are $8,000 and monthly savings are $267, break-even is 8,000 ÷ 267 = approximately 30 months (2.5 years). If you plan to stay in the home beyond that point, the refinance produces net savings. If you sell or refinance again before that point, you will not have recovered the cost.
This simple break-even formula is a useful first filter, but it has limitations. It does not account for the amortization reset effect — the fact that the new loan's early payments are weighted more heavily toward interest than your current loan's payments would be. A more rigorous analysis compares cumulative interest paid under both scenarios, as shown in the worked example below.
The simple break-even also does not consider the time value of money. A more sophisticated analysis discounts both the savings and the closing costs to present value. For most household refinance decisions, the simple break-even is a sufficiently accurate heuristic as long as the amortization reset is separately considered.
Interest Rate Sensitivity
The table below illustrates how monthly payment changes on a $380,000 remaining balance refinanced into a new 30-year loan at various rates. This shows the raw monthly savings relative to a baseline 6.75% rate before closing costs are factored in.
| New Rate | Monthly P&I | Savings vs 6.75% | Break-Even ($8K costs) |
|---|---|---|---|
| 6.75% (current) | $2,466 | — | — |
| 6.25% | $2,340 | $126/mo | 63 months |
| 5.75% | $2,218 | $248/mo | 32 months |
| 5.25% | $2,098 | $368/mo | 22 months |
| 4.75% | $1,981 | $485/mo | 17 months |
| 4.25% | $1,869 | $597/mo | 13 months |
Based on $380,000 remaining balance, 30-year new term, $8,000 closing costs. Figures are approximate.
Closing Costs and How They Are Modeled
Closing costs for a refinance typically range from 2% to 5% of the loan balance and include lender origination fees, appraisal, title search and insurance, recording fees, and prepaid interest. The calculator accepts a single closing cost input representing the total of all these expenses. This figure is then divided by the monthly savings to produce the break-even month.
If closing costs are rolled into the new loan rather than paid upfront, the break-even calculation changes: instead of a lump-sum cost to recover, you are paying a slightly higher monthly payment compared to a scenario where you paid closing costs out of pocket. The effective savings are lower, which extends the break-even period. For buyers considering the full cost landscape of homeownership, the closing costs guide provides a detailed breakdown of every line item.
The Hidden Impact of Resetting Amortization
The amortization reset is one of the most consequential — and most frequently overlooked — aspects of refinancing. When you originate any mortgage, the schedule is structured so that interest is collected heavily in the early years and principal is reduced more aggressively toward the end. This is not arbitrary: it reflects the fact that interest is always calculated on the outstanding balance, which is highest at the beginning of the loan.
As you progress through your existing loan, an increasing share of each payment goes toward principal. By year 15 of a 30-year mortgage, roughly half of each monthly payment is eliminating principal. By year 20, the majority of each payment is principal. When you refinance into a new 30-year loan at year 15, you reset this split back to month one — meaning the new loan's early payments are again mostly interest. Even if the new rate is lower, you may end up paying more total interest over the combined life of both loans than you would have by simply continuing with the original.
| Refinance Timing | Remaining Balance | Years Added to Payoff | Extra Interest Risk |
|---|---|---|---|
| Year 2 of 30 (early) | ~$390K of $400K | ~2 years | Low — minimal reset effect |
| Year 7 of 30 (mid-early) | ~$370K of $400K | ~7 years | Moderate — noticeable reset |
| Year 15 of 30 (midpoint) | ~$330K of $400K | ~15 years | High — significant interest penalty |
| Year 22 of 30 (late) | ~$230K of $400K | ~22 years | Very high — rarely beneficial |
Assumes refinancing into a new 30-year loan. Based on original $400,000 loan at 6.5%. "Extra Interest Risk" is qualitative.
The practical implication: the further along you are in your existing mortgage, the more carefully you need to evaluate a 30-year refinance. Borrowers in the early years of a loan have little to lose from the reset, since their principal reduction has barely begun. Borrowers approaching the midpoint or beyond are often better served by refinancing into a shorter term — a 15-year or 20-year loan — that eliminates the full reset effect and accelerates payoff. The amortization deep-dive guide walks through these schedules with month-by-month examples.
There is one important counterargument: if a homeowner refinances to a lower rate and invests the monthly savings rather than accelerating paydown, the compounding return on invested savings can outpace the extra interest cost of the reset. Whether this argument holds depends on the actual rate reduction, the investment return, and the time horizon. It is worth modeling both scenarios before deciding.
Full Numeric Refinance Example
The following example walks through a realistic refinance scenario step by step, including the break-even calculation and the impact of a further rate change.
Scenario Inputs
Step 1 — Current Monthly Payment
Current loan: $380,000 remaining at 6.75% with 300 months (25 years) remaining. Monthly rate r = 0.0675 ÷ 12 = 0.005625.
Step 2 — New Monthly Payment After Refinance
New loan: $380,000 at 5.75% over 30 years (360 months). Monthly rate r = 0.0575 ÷ 12 = 0.004792.
Monthly savings = $2,647 − $2,218 = $429/month
Step 3 — Break-Even Calculation
If you plan to stay in the home for at least 20 months (under 2 years), the refinance recoups its cost. Beyond that, every month produces $429 in net savings. At 5 years, cumulative net savings (after recovering the $8,000) reach approximately $17,740. At 10 years, cumulative net savings reach approximately $43,480.
Step 4 — Impact of a 1% Rate Increase
Suppose rates rise 1% before you close, making the new rate 6.75% — identical to your current loan. At that point, the new payment equals the old payment (approximately), and the only financial result is paying $8,000 in closing costs for no monthly savings. The break-even becomes infinite: the refinance does not make financial sense. This illustrates how rate-lock timing affects the decision meaningfully.
Key takeaway
In this scenario, a 1% rate reduction (6.75% → 5.75%) on a $380,000 balance produces a break-even at 19 months and roughly $43,000 in cumulative savings over 10 years after closing costs — assuming you stay. A 0.5% reduction narrows the margin substantially and extends the break-even to around 38 months. Always run the math at the rate you can actually lock today, not a projected future rate.
Rate-and-Term vs Cash-Out Refinance
What is the difference between rate-and-term and cash-out refinancing?
A rate-and-term refinance replaces your existing mortgage with a new loan at a different interest rate, a different term, or both — without changing the principal beyond the remaining balance. A cash-out refinance replaces the existing loan with a larger loan, and the difference between the new loan amount and the existing payoff is distributed to the borrower as cash. Both types reset the amortization schedule; only cash-out increases total debt.
Rate-and-Term Refinance
- • New loan pays off existing balance only
- • Lower rate reduces monthly payment and total interest
- • Shorter term increases payment but reduces total interest cost
- • Home equity is preserved or grows faster
- • Generally carries lower rates than cash-out
- • Risk profile is unchanged from original mortgage
Cash-Out Refinance
- • New loan is larger than the existing payoff
- • Difference distributed to borrower as lump sum
- • Home equity is reduced by the cash-out amount
- • Total debt increases — monthly payment may rise
- • Interest rate typically slightly higher than rate-and-term
- • Useful for home improvements, debt consolidation with caveats
Cash-out refinancing is sometimes used to consolidate high-interest consumer debt — credit cards, auto loans, personal loans — into a lower-rate mortgage. While the reduced monthly payment can seem appealing, this strategy converts unsecured debt into debt secured by your home. If financial circumstances change and payments become difficult, the consequences are far more severe than defaulting on an unsecured card. Debt consolidation through cash-out refinance is a decision that warrants careful analysis of total cost, not just monthly cash flow.
Cash-out refinancing also reduces your equity cushion — the buffer that protects you from being underwater if home values decline. Borrowers who cash out aggressively in rising markets have historically found themselves in negative equity positions when prices correct. For a broader view of how home equity interacts with your financial position, the hidden costs of homeownership guide covers equity risk in the context of long-term ownership.
5-Year and 10-Year Scenario Comparison
The same refinance decision produces very different financial outcomes depending on how long you stay in the home. The table below compares three paths using the same $380,000 balance, 6.75% → 5.75% rate scenario, with $8,000 in closing costs paid upfront.
| Metric | Scenario A: Refinance, Stay 10 Yrs | Scenario B: Refinance, Sell Yr 3 | Scenario C: Keep Existing Loan |
|---|---|---|---|
| Monthly P&I payment | $2,218 | $2,218 | $2,647 |
| Closing costs paid | $8,000 | $8,000 | $0 |
| Cumulative payments (10 yr / 3 yr) | $266,160 | $79,848 | $317,640 |
| Total interest paid (period) | ~$148,000 | ~$63,000 | ~$172,000 |
| Closing costs recovered by | Month 19 | Not yet (Month 36 breakeven) | N/A |
| Net savings vs keeping loan (after costs) | +$43,480 | −$2,144 (net loss) | Baseline |
| Remaining balance at end of period | ~$347,000 | ~$371,000 | ~$358,000 |
Scenario A and B use new 30-year loan at 5.75%. Scenario C continues existing 25-year loan at 6.75%. All figures are rounded estimates.
Scenario A — Refinance and Stay 10 Years
This is the scenario where refinancing most clearly wins. After recovering the $8,000 closing cost in month 19, the borrower accumulates approximately $43,480 in net savings over 10 years. The lower monthly payment also frees up $429/month that can be directed toward other financial priorities. The amortization reset is a real cost here — the new loan's principal reduction is slower in years 1–5 — but the rate savings more than compensate over a 10-year period.
Scenario B — Refinance and Sell in Year 3
Selling before the break-even point produces a net financial loss. The borrower paid $8,000 in closing costs and recovered only $429 × 36 = $15,444 in payment savings, giving a gross surplus of $7,444 — but the closing costs of $8,000 exceed this by $556. The borrower would have been slightly better off keeping the original loan if selling at exactly year 3. This margin is thin, and other factors (lower monthly stress, better cash flow) might tip the decision differently — but purely on cost, the refinance in this scenario was marginally unprofitable.
Scenario C — Keep the Existing Loan
Keeping the existing loan is the no-cost baseline. The higher monthly payment ($2,647 vs $2,218) is the only downside, but there are no closing costs and the amortization schedule continues its current trajectory without resetting. For borrowers planning to sell within 18 months, or those who are more than 15 years into their existing loan and would face significant amortization reset costs, staying with the original loan may produce a better outcome than refinancing.
What This Tool Does Not Include
Being transparent about what a model cannot measure is as important as explaining what it can. The following factors are real, material considerations in a refinance decision that fall outside the scope of any standard calculator. They should be evaluated qualitatively alongside the quantitative output.
Tax Deductibility Changes
Mortgage interest may be deductible if you itemize federal taxes, but since the 2017 Tax Cuts and Jobs Act raised the standard deduction significantly, the majority of homeowners no longer itemize. The calculator does not model tax scenarios. If you are in a high-income bracket and do itemize, the after-tax cost of a higher interest rate may be lower than the nominal rate suggests — consult a tax professional for this analysis.
Credit Score Impacts
Applying for a refinance triggers a hard credit inquiry, which temporarily reduces your credit score by a small amount. Multiple applications within a short window (typically 14–45 days depending on scoring model) are usually treated as a single inquiry for mortgage purposes. However, if your credit score is borderline for a preferred rate tier, timing the application relative to other credit events matters.
Market Rate Volatility
Mortgage rates can move meaningfully over days or weeks. The rate you are quoted during initial inquiry may differ from the rate at closing if you do not lock immediately. Rate locks typically last 30–60 days and may carry a cost. A rate increase of even 0.25% between quote and closing can materially change the break-even calculation and, in some cases, make a previously attractive refinance uneconomical.
Future Refinancing Risk
A refinance today does not preclude refinancing again in the future — but it does reset the clock. Borrowers who refinance repeatedly to capture incrementally lower rates can find themselves perpetually in the early, interest-heavy portion of their amortization schedule, never making meaningful progress on principal. This pattern, while providing short-term cash flow relief, can significantly extend the total time to payoff and total interest paid.
Prepayment and Extra Payments
If you make extra principal payments on your current loan, the break-even analysis for refinancing becomes more complex. Extra payments on the existing loan reduce the balance faster and may outperform the savings from a refinance, depending on the rate differential. The calculator does not model prepayment scenarios. For those who plan to make additional payments, the comparison requires a custom schedule analysis.
Liquidity and Opportunity Cost of Closing Costs
Paying $8,000–$15,000 in upfront closing costs has an opportunity cost beyond the break-even calculation. That cash could be invested, used as an emergency fund, or applied to high-interest debt. If the closing costs represent a meaningful portion of your liquid savings, the refinance may reduce your financial resilience even if the long-term math is favorable. This liquidity consideration is not quantified in the standard break-even model.
When Refinancing Makes Financial Sense
Refinancing is most financially compelling when three conditions align: a meaningful rate reduction is available, a significant remaining loan balance means the savings-per-month are material, and the borrower has a long enough time horizon to recover the closing costs well before selling or refinancing again. The following scenarios represent situations where refinancing commonly delivers a clear financial benefit.
Rate reduction of 0.75% or more on a large remaining balance
On a $400,000+ remaining balance, a 0.75–1% rate cut produces $250–$380/month in savings. With typical closing costs of $6,000–$10,000, the break-even falls at 16–40 months — well within a reasonable stay horizon for most homeowners. The larger the balance and the greater the rate reduction, the faster the break-even and the more compelling the case.
Long time horizon remaining — 10 or more years
Borrowers early in their loan term (years 1–8) face the smallest amortization reset penalty, since they have not yet built significant momentum in their principal reduction schedule. A refinance in the early years also has the maximum time horizon to accumulate savings, making the total benefit largest for those who plan to stay and are still in the first third of their original loan term.
Eliminating PMI through improved loan-to-value
Private mortgage insurance (PMI) applies when the loan-to-value ratio exceeds 80%. If your home has appreciated enough that a refinance would be at 80% LTV or below, eliminating PMI adds to the monthly savings calculation. PMI typically costs 0.5–1.5% of the loan amount annually ($150–$450/month on a $360,000 loan), which can transform a marginal refinance decision into a clearly beneficial one.
Switching from adjustable to fixed rate
Borrowers with adjustable-rate mortgages (ARMs) face payment uncertainty when the fixed-rate period expires. Refinancing into a fixed-rate loan at a known rate — even if the current ARM rate is temporarily lower — provides payment certainty and eliminates the risk of sharp payment increases in rising-rate environments. The value of this certainty is real, even if it is difficult to quantify in a standard calculator.
When does refinancing not make sense?
Refinancing generally does not make financial sense in the following situations:
- •You plan to sell within 18–24 months. Unless the rate reduction is very large and closing costs are very low, the break-even will not be reached before the sale, resulting in a net loss from the transaction.
- •You are far into your existing amortization. If you are 20+ years into a 30-year mortgage, restarting a new 30-year term adds decades of interest, even at a lower rate. The total interest paid can be substantially higher than simply completing the existing loan.
- •The rate reduction is minimal (under 0.5%). On a $200,000 balance, a 0.5% reduction saves roughly $60/month. With $5,000 in closing costs, break-even is 83 months — nearly 7 years. A small remaining balance or a small rate improvement may not justify the cost and administrative effort.
- •You have recently refinanced. If you refinanced within the last 12–18 months, refinancing again resets the break-even clock and compounds closing costs. Serial refinancing rarely produces cumulative net savings when total closing costs are tallied across multiple transactions.
When evaluating any refinance, it is worth running the full comparison alongside your broader housing financial picture. If you are also weighing whether to sell and rent vs continue owning, the rent vs buy calculator provides the full context for that decision. If you are evaluating your overall housing budget and what you can comfortably afford, the home affordability calculator is a useful companion tool.
Step-by-step refinance decision framework
- 1Calculate your current remaining balance and monthly P&I from your most recent mortgage statement.
- 2Identify the new rate you can realistically lock today — not a projected future rate.
- 3Estimate total closing costs from at least two lenders (2–5% of loan balance is typical).
- 4Calculate the monthly savings (current payment − new payment) and divide closing costs by that figure to find your break-even month.
- 5Compare the break-even month to your realistic time horizon in the home.
- 6Run the scenario with a 0.5% higher rate to stress test: if the break-even extends beyond your horizon, the decision is fragile.
- 7Separately evaluate the amortization reset: how many years of principal-building momentum would you forfeit?
- 8Consider whether a 15-year or 20-year term better aligns with your payoff goals, even if the monthly payment is higher.
Frequently Asked Questions
How do you calculate the refinance break-even point?
The break-even point is calculated by dividing the total closing costs of the refinance by the monthly payment savings. For example, if your closing costs are $8,000 and you save $267 per month, your break-even is 8,000 ÷ 267 = approximately 30 months. If you plan to stay in the home beyond that point, the refinance saves money in the long run.
Does refinancing reset your amortization schedule?
Yes. Every refinance starts a new amortization schedule from month one. This means early payments on the new loan are again weighted heavily toward interest rather than principal. If you are 15 years into a 30-year mortgage and refinance into a new 30-year loan, you effectively add 15 years to your payoff timeline and pay substantial additional interest over the life of the loan, even if the monthly payment is lower.
What is a good interest rate to refinance at?
There is no universal threshold. The question is not what rate you can get but whether the savings justify the cost. A common guideline is that a reduction of at least 0.5% to 1% in interest rate may make refinancing worth evaluating, but the decision depends equally on your remaining loan balance, how long you plan to stay, your closing costs, and how far along you are in your existing amortization schedule.
What is the difference between rate-and-term and cash-out refinancing?
A rate-and-term refinance replaces your existing loan with a new one at a different interest rate, different term, or both — without extracting equity. A cash-out refinance replaces your loan with a larger loan, allowing you to receive the difference as cash. Cash-out refinancing reduces your home equity, typically comes with slightly higher rates, and converts home equity into debt. Both reset your amortization schedule.
Should I refinance into a 15-year or 30-year mortgage?
A 15-year mortgage typically carries a lower interest rate and dramatically reduces total interest paid, but monthly payments are significantly higher — often 30–40% more than a 30-year loan at similar rates. A 30-year refinance lowers the monthly payment more aggressively and preserves cash flow flexibility, but the total interest cost over the life of the loan is much higher. The right choice depends on your cash flow, financial goals, and how long you plan to keep the loan.
Data Sources & Methodology
Freddie Mac Primary Mortgage Market Survey
Weekly mortgage rate historical data
Consumer Financial Protection Bureau (CFPB)
Mortgage closing cost guidelines and borrower protections
Federal Reserve Economic Data (FRED)
Historical interest rate and economic data
Fannie Mae Loan Performance Data
Refinance activity and amortization modeling benchmarks
All calculation methodology is documented in detail on our methodology page. Numeric examples in this guide are rounded for readability and are intended as illustrative estimates only.
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Disclaimer: This content is provided for educational purposes only and does not constitute financial, tax, or investment advice. Calculator outputs and numeric examples are estimates based on assumptions and may not reflect individual circumstances. Mortgage rates, closing costs, and loan terms vary by lender, credit profile, and market conditions. Consult a qualified financial or mortgage professional before making any refinancing decision.