Refinance Calculator - Monthly Savings & Break-Even
Use this refinance calculator to compare current and proposed payments, monthly savings, scheduled interest, and closing-cost break-even in one estimate.
Refinance Calculator
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What Is Refinance Calculator?
A refinance calculator compares the scheduled cost of your current fixed-rate loan with a proposed replacement loan. Enter the remaining balance, current rate, years left, new rate, new term, and expected closing costs. The estimate shows payment change, scheduled interest, rate reduction, and the number of months needed to recover upfront costs. Use it before requesting quotes so you can test assumptions consistently, not as a promise that a lender will approve or offer those terms.
- • Screen a rate reduction: Compare a lower proposed rate with the loan you already have. Monthly savings can show whether a quote deserves closer review, while rateReduction confirms the difference in percentage points.
- • Test a new term: Try a 15-, 20-, or 30-year replacement term. A shorter term may raise the payment but reduce scheduled interest; a longer term may lower the payment while extending repayment.
- • Check closing-cost recovery: Enter lender fees and other upfront refinance costs to estimate break-even. Compare the resulting months with how long you expect to keep the loan or home.
- • Compare a loan offer: Run the same balance and costs against more than one rate or term. Put the calculator beside each Loan Estimate to identify which assumptions change payment and net interest most.
The model is for fixed-rate principal-and-interest comparisons. It does not automatically add property taxes, insurance, mortgage insurance, escrow, or other items in a real payment. It treats the current balance as the amount refinanced, so cash-out proceeds, financed costs, or a payoff statement need separate adjustments.
If you want to compare two mortgage offers beyond a refinance scenario, use the mortgage comparison calculator to line up their rates, terms, and payments.
How Refinance Calculator Works
The calculator models each loan independently with level-payment amortization, then compares the two schedules. Rates are converted from annual percentages to monthly decimals, and terms are converted from years to monthly payment counts.
- P: The current remaining principal balance used for both schedules.
- r: The monthly decimal rate: annual rate ÷ 100 ÷ 12.
- n: The number of monthly payments: term in years × 12.
- M: The fixed monthly principal-and-interest payment for one schedule.
For a zero-percent rate, the regular expression has a zero denominator, so the function uses P ÷ n instead. That gives $833.33 per month for $100,000 at 0% over 120 months before display rounding. If savings are zero or negative, break-even returns 0 for the interface to render as “N/A — no positive monthly savings.”
The Consumer Financial Protection Bureau describes mortgage payment calculation as a function of loan amount, rate, and payment count. This calculator follows that principal-and-interest approach and keeps unrounded totals until final currency formatting.
Example: lower rate over the same remaining term
$250,000 balance, 6.50% current rate, 25 years remaining, 5.00% new rate, 25-year new term, and $5,000 closing costs.
The current schedule produces about $1,688.02 per month and $256,405.37 of scheduled interest. The proposed schedule produces about $1,461.48 per month and $188,442.53 of scheduled interest. Payment savings are $226.54 per month; ceiling($5,000 ÷ $226.5428) gives 23 months.
Gross scheduled interest falls by $67,962.84. After $5,000 of costs, modeled net interest savings are $62,962.84, with a 1.50 percentage-point rate reduction.
This scenario looks favorable under the entered assumptions if the borrower keeps the replacement loan beyond the 23-month break-even point. Verify that the quoted costs, rate, and term match the lender’s disclosures.
According to Consumer Financial Protection Bureau, mortgage lenders calculate the monthly principal-and-interest payment from the loan amount, interest rate, and number of payments using a standard amortization formula.
Use the amortization calculator when you need a payment-by-payment view of how principal and interest change over the selected schedule.
Key Concepts Explained
Four ideas help you read the comparison without treating one attractive number as the whole decision.
Monthly payment savings
This is currentPayment minus newPayment. A positive amount lowers the scheduled principal-and-interest payment; a negative amount means the replacement schedule requires more each month.
Break-even period
Break-even divides closing costs by positive monthly savings and rounds up to a whole month. It is a recovery timeline, not a projection of lifetime savings or a measure of loan approval.
Scheduled interest
Each totalInterest value is the modeled payment total minus the shared principal. Comparing currentInterest and newInterest reveals the cost of each selected schedule before adding or subtracting other transaction items.
Term tradeoff
A new term changes the number of payments. Resetting a nearly paid-off loan to a longer term can lower the monthly payment while increasing the repayment horizon and sometimes the total interest.
Gross interest difference and net interest savings are separate. Gross difference is currentInterest minus newInterest; netInterestSavings also subtracts closingCosts. A refinance can lower payments but produce negative net savings when costs are high, the term is longer, or the borrower leaves before recovery.
Amortization means early payments contain relatively more interest and later payments more principal. Use the current payoff amount and remaining term rather than original mortgage figures.
For a more focused closing-cost timeline, the refinance break-even calculator can help you explore how costs and monthly savings affect recovery time.
How to Use This Calculator
Use recent loan documents and a realistic cost estimate. Small changes in the remaining balance, term, or financed fees can materially change payment and interest results.
- 1 Enter the current balance: Use the remaining principal or a current payoff estimate. Do not substitute the original amount borrowed.
- 2 Enter current loan terms: Add the current fixed annual rate and years remaining. If the term is expressed in months, divide by 12 for this estimate.
- 3 Enter proposed terms: Add the quoted new annual rate and full replacement term. Use the same rate basis and confirm whether the quote is fixed.
- 4 Add closing costs: Include the costs you will pay or finance, including points when you choose to treat them as upfront refinance costs.
- 5 Read payment and interest together: Review monthlySavings, breakEvenMonths, currentInterest, newInterest, and netInterestSavings. If the payment is higher, read break-even as N/A rather than as zero months.
A practical quote check: Suppose your payoff balance is $300,000 at 7.25% with 30 years remaining, and a lender proposes 6.25% for 20 years with $7,000 in costs. The modeled new payment is about $146.26 higher, so there is no positive payment-savings break-even and the interface should say N/A. Scheduled interest falls by about $210,482.08, leaving net savings of about $203,482.08 after costs. This supports a faster-payoff decision, not a lower-payment decision.
If the new loan also releases equity, switch to a cash-out refinance calculator so the additional borrowing is included in the comparison.
Benefits of Using This Calculator
A consistent comparison makes a refinance conversation more concrete, especially when two offers differ in rate, term, or upfront costs.
- • Separate cash-flow and lifetime decisions: Monthly savings focuses on the recurring payment, while net interest savings focuses on modeled schedule cost after closing costs. Seeing both prevents one goal from hiding the other.
- • Put a time horizon on costs: The break-even month gives you a simple checkpoint to compare with your expected time in the home or loan. Revisit it if fees are financed or the quote changes.
- • Test shorter payoff plans: Compare a shorter replacement term to see the payment required to reduce scheduled interest faster. A higher payment can still be rational when accelerated payoff is the objective.
- • Compare offers consistently: Use the same balance, cost treatment, and term assumptions for several quotes. This makes differences in rate and fees easier to isolate before a lender discussion.
- • Spot misleading low payments: A longer replacement term can lower the monthly number by spreading repayment over more months. The current and new interest outputs expose that tradeoff instead of presenting payment alone.
The tool is a screening worksheet. After finding a promising scenario, ask the lender how rate, points, lender credits, cash needed to close, and loan amount affect the official offer. For cash flow, prioritize payment and break-even; for interest reduction, give term and net savings more weight.
Factors That Affect Your Results
The result is sensitive to the assumptions you enter and to items that a simple fixed-payment comparison cannot price.
Rate difference
A lower new rate generally reduces the replacement payment and scheduled interest for the same balance and term, but the size of the effect depends on the payment count.
Remaining balance
A larger balance usually creates larger dollar payments, interest totals, and potential savings. Use the current payoff amount so the comparison is tied to the debt being replaced.
Replacement term
Shorter terms can raise the payment while reducing interest; longer terms can lower the payment while extending the schedule. Compare terms that fit your budget and payoff objective.
Closing costs
Higher costs lengthen break-even and reduce net interest savings. Include points, lender fees, and other upfront amounts consistently, whether paid in cash or financed.
Time you keep the loan
A refinance may not recover its costs if you sell, refinance again, or pay off the loan before the estimated break-even month. Compare the timeline with your plans.
- • This estimate excludes taxes, insurance, escrow, prepayments, points, penalties, lender credits, APR, and eligibility unless you separately reflect an amount in the inputs. Taxes, insurance, escrow, points, penalties, lender credits, APR and eligibility may differ between loans and lenders.
- • The calculation uses the same current balance for both schedules and assumes fixed rates, regular monthly payments, and no missed payments. It does not model cash-out proceeds, mortgage insurance changes, daily interest, servicing fees, prepaid escrow, or a lender-specific payoff quote.
- • A no-closing-cost refinance is not automatically free. The Consumer Financial Protection Bureau explains that a lender may offset costs through a higher rate or by adding costs to the loan balance, so compare the complete offer rather than entering zero without checking the disclosure.
Use the Loan Estimate to validate the proposed loan amount, rate, projected payment, cash to close, and charges. The Consumer Financial Protection Bureau says it helps consumers compare key terms, projected payments, and estimated closing costs before choosing a mortgage.
According to Consumer Financial Protection Bureau, The Consumer Financial Protection Bureau says a Loan Estimate helps consumers compare key loan terms, projected payments, and estimated closing costs before choosing a mortgage.
According to Consumer Financial Protection Bureau, The Consumer Financial Protection Bureau notes that a no-cost refinance is not free because the lender may cover closing costs by charging a higher interest rate or adding costs to the loan balance.
Use a mortgage calculator to explore a broader mortgage payment scenario when taxes, insurance, or purchase assumptions need to be modeled separately.
Frequently Asked Questions
Q: How does a refinance calculator estimate monthly savings?
A: It calculates a fixed principal-and-interest payment for the current schedule and another for the proposed rate and term. It subtracts the new payment from the current payment. The result is positive when the modeled replacement payment is lower and negative when it is higher.
Q: How do you calculate the break-even point for refinancing?
A: Divide refinance closing costs by positive monthly payment savings, then round up to the next whole month. If savings are zero or negative, costs cannot be recovered through payment savings, so this calculator returns 0 and the interface labels the result N/A.
Q: What closing costs should I include in a refinance calculation?
A: Use the upfront costs that belong to the refinance comparison, such as lender fees, appraisal, title work, recording charges, and points you treat as a cost. Check the Loan Estimate, and decide consistently whether financed costs increase the replacement balance.
Q: Can refinancing lower my payment but increase total interest?
A: Yes. A longer replacement term can spread the balance across more payments, lowering the monthly amount while increasing scheduled interest. Compare currentInterest, newInterest, and netInterestSavings instead of judging the refinance by payment savings alone.
Q: Does refinancing restart the mortgage amortization term?
A: Usually, a new mortgage has its own replacement term and amortization schedule. Choosing a term longer than the years left on your current loan can extend repayment even when the rate and payment are lower. Compare the new term with your payoff plans.
Q: Are no-closing-cost refinances really free?
A: Not necessarily. A lender may cover or reclassify closing costs by charging a higher interest rate or adding costs to the balance. Compare the complete Loan Estimate, including rate and loan amount, rather than assuming a zero-cost entry means no economic cost.