🔄 Refinance Calculator

Compare your current loan to a new refinanced loan — see your monthly savings, break-even point on closing costs, and lifetime interest savings.

🔄 Loan Details
Current Loan
$
Enter a remaining balance greater than $0.
%
yrs
$
Auto-filled from balance/rate/term — edit if your actual statement payment differs
New (Refinanced) Loan
%
Enter a rate greater than 0%.
yrs
Enter a term of at least 1 year.
$
$
📈 Results
New Monthly Payment
Monthly Savings
Break-Even Point
Lifetime Interest Savings

Current vs New Loan

Current Monthly Payment
New Monthly Payment
Current Loan Remaining Interest
New Loan Total Interest (full term)
Closing Costs
Net Lifetime Savings
Current vs New: Payment & Interest
Cumulative Savings Over Time
Figures are estimates based on the rates and terms you enter — actual lender quotes, fees, and underwriting terms will vary. Not financial advice.
🔄

Enter Your Loan Details

Fill in your current loan and the new refinance terms, then click Calculate Refinance.

Guide

What Is the Refinance Calculator?

Last updated: July 2026 · Reviewed by the NeftCal editorial team

A refinance calculator compares your current loan — mortgage, auto, or personal — against a new refinanced loan, so you can see whether switching actually saves you money once closing costs are factored in. It's built for borrowers who've been offered a lower rate and want to know if it's really worth it, not just whether the monthly payment looks smaller. This break-even refinance calculator turns that question into two hard numbers: how many months it takes to recoup your closing costs, and how much you'd actually save (or lose) over the life of both loans.

Enter your current loan's remaining balance, rate, and remaining term — the calculator auto-computes your current monthly payment, which you can override if your actual statement payment differs. Then enter the new loan's rate, term, closing costs, and any cash-out amount you want to borrow against your equity. The calculator computes your new monthly payment using the standard amortization formula on the new principal (remaining balance plus cash-out), then fully amortizes both the current loan (over its remaining term) and the new loan (over its new term) to compare real total interest costs, not just the headline payment.

Who Should Use This Calculator

This tool is for homeowners who've received a refinance offer or noticed rates have dropped, auto loan borrowers checking whether a dealer or bank refinance offer is worth the paperwork, and anyone considering a cash-out refinance to access equity. It's equally useful for a quick "is this worth it?" gut check and for a detailed side-by-side comparison before signing new loan documents.

Why It Matters for Financial Planning

A lower monthly payment doesn't always mean a better deal — refinancing resets your amortization clock, and stretching back out to a long term can mean paying more total interest even at a lower rate. This calculator's break-even point tells you exactly how many months of savings it takes to recoup your closing costs, and the lifetime interest savings figure nets those costs against the true interest difference over the life of both loans, so you can see the full picture before committing to a should-I-refinance decision.

Common Scenarios

  • Comparing a lender's refinance offer against your current mortgage to see the real break-even point
  • Deciding between a no-closing-cost refinance and paying fees upfront for a lower rate
  • Sizing a cash-out refinance to fund a renovation and checking the new payment impact
  • Refinancing an auto loan after a credit score improvement lowers your available rate
  • Checking whether extending back to a fresh 30-year term erases the benefit of a lower rate

Tips for Accurate Results

  • Use your actual current statement payment if it differs from the auto-computed figure — some loans include escrow, extra principal, or rounding that changes the real number
  • Get an accurate closing costs estimate from your lender's Loan Estimate document rather than guessing — this drives the break-even calculation directly
  • If you plan to move or pay off the loan before the break-even point, refinancing usually isn't worth it even with a lower rate
  • Watch the total interest comparison, not just the monthly payment — a longer new term can quietly increase your lifetime interest cost
  • Enter a Cash-Out amount only if you actually intend to borrow more — it directly increases your new principal and payment
Formula

How Refinance Savings Are Calculated

Break-even compares upfront closing costs against ongoing monthly savings

New Loan Principal & Payment
New Principal = Remaining Balance + Cash-Out
New Payment = P × r × (1 + r)ⁿ / [(1 + r)ⁿ − 1]

Monthly Savings & Break-Even
Monthly Savings = Current Payment − New Payment
Break-Even (months) = Closing Costs ÷ Monthly Savings

Lifetime Interest Savings
Lifetime Savings = (Current Loan Remaining Interest − New Loan Total Interest) − Closing Costs

Where: P = new principal, r = new monthly rate (annual rate ÷ 12 ÷ 100), n = new term in months
⏱️

Break-Even Point

The number of months it takes your monthly savings to fully offset the closing costs you paid to refinance. Staying in the loan past this point is where refinancing starts to pay off.

💵

Cash-Out Refinance

Adding a Cash-Out amount increases your new loan's principal above your current balance, giving you the difference in cash — but it also increases your new payment and total interest.

⚠️

The Amortization Reset

Refinancing restarts your loan's amortization clock. Even at a lower rate, extending back out to a long term can raise your total lifetime interest despite a lower monthly payment — always check both numbers.

📊

Full Amortization Comparison

Rather than just comparing rates, the calculator amortizes both the current loan (over its remaining term) and the new loan (over its new term) in full to compute true total interest on each.

⚙️ Why This Formula Works

The new payment uses the same reducing-balance annuity formula that prices any amortized loan: a fixed periodic payment, discounted at the periodic rate over n periods, must equal the principal. Break-even is simple division — closing costs divided by the monthly cash-flow savings tells you how many months of that savings it takes to cover what you paid to get it. Lifetime savings goes a level deeper: it fully amortizes both loans month by month (using amortizeToPayoff-style simulation) to sum actual total interest paid on each, then nets the difference against closing costs — capturing the term-reset effect that a simple rate comparison misses.

🎯 When to Use It

  • You've received a refinance offer and want to check the real numbers, not just the advertised rate
  • You're deciding between paying closing costs upfront or rolling them into a no-closing-cost refinance
  • You want to compare a cash-out refinance's added cost against the cash you'd receive
  • You're refinancing any fixed-rate installment loan — mortgage, auto, personal, or student loan

📋 Assumptions

  • Both the current and new loan have a fixed interest rate for their full term
  • Payments are made on schedule every month with no missed or extra payments
  • Closing costs are paid upfront in cash, not rolled into the new loan balance
  • The current loan's remaining interest is calculated by amortizing it forward at its existing payment

⚠️ Limitations of the Formula

  • Doesn't model property taxes, PMI, HOA fees, or homeowners insurance — principal and interest only
  • Doesn't account for tax deductibility of mortgage interest or points paid
  • Assumes closing costs are a flat dollar figure, not a rolled-in balance increase
  • Doesn't factor in your credit score, DTI, or approval odds for the new rate
Walkthrough

Step-by-Step: How to Use the Refinance Calculator

From your current loan to a break-even date in under a minute

Enter your current loan details

Input your remaining balance, current interest rate, and remaining term. The calculator auto-computes your current monthly payment — override it with your actual statement payment if escrow or extra principal makes it differ.

Enter the new loan's rate and term

Input the interest rate and term offered on the refinanced loan. It doesn't need to match your remaining term — you can shorten or extend it.

Add closing costs and any cash-out amount

Enter the total upfront fees to refinance from your Loan Estimate, plus any extra amount you want to borrow on top of your remaining balance.

Click Calculate Refinance

The calculator computes your new monthly payment, fully amortizes both the current and new loan, and works out your break-even point and lifetime interest savings.

Review your break-even point and lifetime savings

Check the break-even month and date, monthly savings, and lifetime interest savings net of closing costs — plus the current-vs-new chart and cumulative savings line — before deciding whether to refinance.

Example

Worked Example

The calculator's own default scenario, computed step by step

Scenario

A $250,000 remaining balance at 6.75% with 25 years left, refinanced into a new 25-year loan at 5.75%, with $4,000 in closing costs and no cash-out.

Remaining Balance$250,000
Current Rate6.75%
Remaining Term25 yrs
New Rate5.75%
New Term25 yrs
Closing Costs$4,000
Step 1 — Current monthly payment: With r = 6.75/12/100 = 0.005625 and n = 300 months, Payment = 250,000 × 0.005625 × (1.005625)³⁰⁰ / [(1.005625)³⁰⁰ − 1] ≈ $1,727.28.
Step 2 — New monthly payment: New Principal = $250,000 + $0 cash-out = $250,000. With r = 5.75/12/100 = 0.0047917 and n = 300, New Payment ≈ $1,572.77. Monthly Savings = $1,727.28 − $1,572.77 = $154.51.
Step 3 — Break-even point: Break-Even = Closing Costs ÷ Monthly Savings = $4,000 ÷ $154.51 ≈ 25.9, rounded up to 26 months (about 2.2 years).
Step 4 — Lifetime interest savings: Amortizing the current loan at its existing payment gives total remaining interest of $268,183.64. Amortizing the new loan at its new payment gives total interest of $221,829.80. Lifetime Savings = ($268,183.64 − $221,829.80) − $4,000 = $42,353.84.
Monthly Savings
$154.51
Break-Even Point
26 months
Lifetime Savings
$42,353.84
MetricCurrent LoanNew Loan
Monthly Payment$1,727.28$1,572.77
Month 1 Interest$1,406.25$1,197.92
Month 1 Principal$321.03$374.85
Total Interest (full term)$268,183.64$221,829.80

Explanation: Even though the rate only drops by a full percentage point (6.75% to 5.75%), the monthly savings of $154.51 recoups the $4,000 closing costs in a little over two years — well within a typical multi-year mortgage holding period. Because both loans use the same 25-year term here, there's no amortization-reset penalty: the $42,353.84 in lifetime savings reflects a genuinely cheaper loan, not a shorter-term illusion. If the new loan had instead reset to a fresh 30-year term, the lower monthly payment would look even better, but total interest paid could rise instead of fall — always check both numbers side by side.

Interpretation

Understanding Your Results

What your break-even point actually tells you about a refinance decision

The break-even point — how many months it takes your monthly savings to repay your closing costs — is the single most useful number for judging a refinance, because it directly answers "how long do I need to keep this loan for the switch to pay off?"

Break-Even PointGeneral ReadTypical Context
Under 24 monthsStrong case for refinancingLarge rate drop, low closing costs, or both
24 – 48 monthsWorth it if you're staying putTypical mortgage or auto refinance with moderate savings
Over 48 monthsOnly worth it for long holdersSmall rate drop, high closing costs, or a short remaining term

If you plan to move or pay off the loan soon: compare your expected timeline against the break-even point. Refinancing rarely makes sense if you'll sell, move, or pay off the loan before you cross that threshold, no matter how attractive the new rate looks.

If lifetime interest savings is negative: even with positive monthly savings, a longer new term can produce a negative lifetime savings figure once closing costs and the extended amortization schedule are factored in. Treat lifetime savings, not just monthly savings, as the deciding number for a long-term hold.

If there's no break-even point: when the new payment isn't lower than the current one, the calculator can't compute a break-even from monthly savings alone. In that case, weigh the lifetime interest figure and any cash-out amount instead — refinancing can still make sense to shorten your term or access equity even without a lower payment.

ℹ️

This tool provides general financial estimates for educational purposes only and does not constitute personalized financial advice. Actual lender quotes, fees, underwriting terms, and closing costs will vary — confirm final figures with your lender before committing to a refinance.

Use Cases

Practical Use Cases for the Refinance Calculator

Where this refinance calculator earns its keep

🏠

Mortgage rate-drop refinance

Check whether a lower advertised rate actually beats your current loan once fees are included.

🚗

Auto loan refinance

Compare a new auto loan offer against your current car payment after a credit score improvement.

💵

Cash-out refinance planning

See exactly how much a cash-out amount raises your new payment and total interest.

🆓

No-closing-cost comparison

Weigh a zero-fee refinance with a slightly higher rate against paying costs upfront.

Term-shortening refinance

Model refinancing into a shorter term to build equity faster despite a higher payment.

📅

Move-timeline check

Compare your expected time in the home or loan against the break-even point before committing.

💼

Personal & student loan refinance

Apply the same break-even math to any fixed-rate installment loan, not just a mortgage.

📊

Lender offer comparison

Run multiple lenders' quoted rates and fees through the calculator to find the best break-even.

Pros & Cons

Advantages and Limitations

What this refinance calculator does well, and where it can't replace professional advice

✅ Advantages

  • Computes a real break-even point in months and an estimated date, not just a rule of thumb
  • Fully amortizes both loans to compare true total interest, not just monthly payment
  • Catches the amortization-reset trap where a lower payment hides higher lifetime interest
  • Lets you override the auto-computed current payment with your real statement figure
  • Supports cash-out refinances by adding the amount directly to new principal
  • Flags when a refinance doesn't actually lower your monthly payment
  • Visual charts for payment/interest comparison and cumulative savings over time
  • Free, instant, and requires no signup or personal information
  • Runs entirely in your browser — your loan details are never sent to a server
  • Works for mortgages, auto loans, personal loans, and student loans alike
  • Downloadable plain-text summary of your full refinance comparison

⚠️ Limitations

  • Doesn't include property tax, PMI, HOA fees, or homeowners insurance
  • Doesn't account for tax deductibility of mortgage interest
  • Assumes closing costs are paid in cash upfront, not rolled into the new balance
  • Doesn't factor in your credit score, DTI ratio, or approval odds for the quoted rate
  • Assumes a fixed rate for both loans — can't model adjustable-rate refinances
  • Results are estimates — actual lender underwriting and fees will vary
  • Not a substitute for a formal Loan Estimate or licensed financial advice
  • Doesn't model prepayment penalties some current loans may carry
Reference

Refinance Options Compared

Quick-reference comparison of common refinance approaches

FeatureRate-and-Term RefinanceCash-Out RefinanceNo-Closing-Cost Refinance
GoalLower rate and/or change termAccess equity as cashAvoid upfront fees
New principalSame as remaining balanceRemaining balance + cash-outSame or fee-inflated balance
Upfront costClosing costs paid in cashClosing costs paid in cash$0 upfront, rolled into rate/balance
Monthly paymentUsually lowerOften higher due to larger principalOften slightly higher than rate-and-term
Best forLong-term holders chasing rate savingsFunding renovations, debt consolidationShort-term holders who won't reach normal break-even

Common Mistakes and Expert Tips

❌ Common Mistakes

  • Comparing only the new interest rate without factoring in closing costs
  • Ignoring the amortization-reset effect of extending back to a long new term
  • Using the auto-computed current payment when your real statement payment differs
  • Refinancing shortly before planning to sell or move, before reaching break-even
  • Forgetting that a cash-out amount increases both payment and total interest
  • Not shopping multiple lenders' closing costs before committing to one

💡 Expert Tips & Best Practices

  • Always compare lifetime interest savings, not just the monthly payment difference
  • Get a real Loan Estimate for closing costs rather than estimating them
  • Match the new term to your actual plans — shorten it if you want to build equity faster
  • Re-run the calculator with a couple of different lender quotes to compare break-even points
  • If you're close to your break-even threshold on timeline, lean conservative and skip refinancing
FAQ

Frequently Asked Questions

Common questions about loan refinancing

When does refinancing make sense?
As a rule of thumb, refinancing tends to make sense when you can recoup your closing costs through monthly savings within a few years and you plan to keep the loan (or stay in the home) at least that long. This calculator's break-even point tells you exactly how many months that takes for your numbers.
What is a no-closing-cost refinance?
A no-closing-cost refinance rolls the closing costs into the loan balance or accepts a slightly higher interest rate instead of paying fees upfront. It can make sense if you don't plan to keep the loan long enough to reach a normal break-even point, but you'll typically pay more in total interest over time in exchange.
What is a cash-out refinance?
A cash-out refinance replaces your loan with a larger one and gives you the difference in cash, using your collateral (like home equity) to borrow more. It increases your principal and typically your monthly payment, so this calculator's Cash-Out field adds that amount directly to your new loan principal before computing the new payment.
Does refinancing reset my amortization clock?
Yes — a new loan term starts fresh, and if you extend back out to a long term (say, restarting a 30-year clock after already paying down several years), your monthly payment can drop even at a lower rate while your total interest paid actually increases. This calculator explicitly compares total interest, not just the monthly payment, so you can catch this common refinancing mistake before committing.
What's the difference between Remaining Term and New Term?
Remaining Term is how many years are left on your current loan as it stands today; New Term is the length of the brand-new refinanced loan starting from today. They don't have to match — you can refinance a loan with 22 years left into a fresh 30-year term, which lowers your payment but resets the payoff clock.
Why does the calculator let me override my Current Monthly Payment?
The auto-computed figure only reflects principal and interest on the balance, rate, and term you enter. Your actual statement payment may include escrow for taxes and insurance, extra principal payments, or a slightly different original schedule, so overriding it keeps the comparison accurate to your real numbers.
What if my new payment isn't actually lower than my current one?
If Monthly Savings comes out to zero or negative, there's no break-even point to calculate from monthly savings alone, and the calculator flags this with a warning. In that case, compare the lifetime interest and any cash-out amount instead — refinancing can still make sense to shorten your term or access equity even without a lower payment.
How is Lifetime Interest Savings different from Monthly Savings?
Monthly Savings is just the payment difference. Lifetime Interest Savings fully amortizes both loans to their payoff dates, totals the interest paid on each, and nets the difference against your closing costs — giving you the true dollar impact of refinancing over the life of the loan, not just your month-to-month cash flow.
Does the calculator account for property taxes, PMI, or insurance?
No — it models principal and interest only, based on the balance, rate, and term you enter. If your statement payment includes escrow for taxes or insurance, use the Current Monthly Payment override field to capture your real total payment for a more accurate comparison.
What do the bar chart and line chart show?
The bar chart compares your current and new loan's monthly payment and total interest side by side. The line chart plots cumulative savings over time (monthly savings × months, minus closing costs) so you can see visually where the curve crosses zero — that crossing point is your break-even month.
Can I use this for an auto loan or personal loan refinance, not just a mortgage?
Yes — the underlying math (remaining balance, rate, term, and standard amortization) applies to any fixed-rate installment loan, so you can use it to compare refinancing an auto loan, personal loan, or student loan just as easily as a mortgage.
Is there a limit to how far ahead the calculator projects?
Internally, amortization projections cap at 600 months (50 years) to avoid an infinite loop if a payment doesn't even cover the accruing interest. In that edge case, the loan effectively never pays off under the terms you entered, and the calculator's totals reflect that cap.
Learn More

Authoritative Resources on Refinancing

Official guidance to complement this calculator — not a substitute for licensed financial advice

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