Home Refinance Cost Calculator: Compare Break-Even

A home refinance cost calculator comparison helps estimate a new loan’s monthly principal-and-interest payment, total interest, and how long it may take monthly savings to offset refinancing costs. Enter the proposed loan amount, APR, term, and estimated closing costs; the results are estimates, not a lender quote or a full comparison of every loan feature.

Formula

The calculator compares a hypothetical refinanced loan’s scheduled payment and interest with user-entered estimates of costs and monthly savings. It does not determine whether refinancing is suitable for a particular borrower.

• Monthly payment = round(P × r ÷ [1 − (1 + r)⁻ⁿ], 2).
• Total interest = monthly payment × n − P.
• Simple break-even time = refinance costs ÷ monthly savings.

P is the new loan amount in dollars; r is the monthly interest rate, calculated as APR ÷ 1,200; and n is the term in months, calculated as years × 12. APR is entered as a percentage per year. The break-even output is in months: “cost” is the estimated one-time refinance cost in dollars, while “save” is the estimated monthly reduction in comparable housing-loan payments in dollars. This simple calculation requires savings greater than zero.

Worked Example

Using the defaults—$300,000, 6.5% APR, 30 years, $6,000 in estimated costs, and $100 in estimated monthly savings:

1. Convert APR to a monthly rate: 6.5 ÷ 1,200 = 0.0054167.
2. Convert the term to months: 30 × 12 = 360.
3. Apply the payment formula: round[300,000 × 0.0054167 ÷ (1 − (1 + 0.0054167)⁻³⁶⁰), 2] = $1,896.20 per month.
4. Calculate total interest using the rounded payment: $1,896.20 × 360 − $300,000 = $382,632.00.
5. Divide costs by monthly savings: $6,000 ÷ $100 = 60 months, or five years.

Assumptions

• The APR and loan payment stay fixed throughout the term.
• Payments are level monthly payments, made at the end of each monthly period.
• Interest accrues monthly using APR divided by 12; the APR is treated as a nominal annual rate for this calculation.
• The calculation excludes taxes, homeowners insurance, mortgage insurance, escrow, and loan-specific fees beyond the cost estimate entered. It does not model prepaid interest, discount points, cash-out proceeds, or changes in property costs.

How to Compare Refinance Calculators

Calculators can appear to disagree because they may measure different things. A payment calculator usually computes principal and interest from a loan balance, rate, and term. A refinance comparison may also account for closing costs, the existing loan’s remaining payments, a changed payoff date, or the time value of money. Check each calculator’s inputs and definitions before comparing its output.

• Match the loan amount. A new loan might include a balance payoff, financed costs, or cash taken out. Use the proposed principal rather than assuming it equals the current balance.
• Use a consistent APR and term. Confirm whether the tool asks for an interest rate or APR, and enter the same proposed repayment period in each comparison.
• Check what “savings” means. Lower monthly principal and interest is not necessarily lower total borrowing cost. A longer term can reduce the payment while extending repayment.
• Find out how costs are treated. Some tools subtract costs from savings, while others add them to the loan balance. Financing costs raises the amount borrowed and can add interest.
• Compare the same scope. A principal-and-interest estimate should not be compared with a payment that includes taxes, insurance, or escrow.

Obtain proposed loan terms and itemized charges from the lender for the figures you enter. Rates, costs, and loan terms vary by offer and situation; this calculator supplies no market quote or approval prediction.

Understanding Break-Even and Total Cost

The break-even result is a simple division: one-time costs divided by monthly savings. With $6,000 of costs and $100 in monthly savings, it takes 60 months for cumulative savings to equal those costs, assuming the estimated savings remain unchanged. The result is not a promise that costs will be recovered: if the loan is paid off or replaced earlier, the simple break-even point may not be reached.

This estimate also leaves out the value of money over time and any differences between the old and new loan’s remaining schedules. For a fuller comparison, compare projected cash outlays over the period you expect to keep the loan, including remaining payments on the existing loan and costs paid or financed on the new one. A shorter new term may have a higher payment but less time accruing interest; a longer term may lower the payment yet leave more payments ahead. These are arithmetic differences, not a recommendation.

The total-interest figure shown is the interest over the entire new term, based on the entered principal, APR, and term. It is not the savings versus the current mortgage. To calculate that comparison, you need the current balance, current rate, remaining term, payment, and applicable costs. Compare like with like, and avoid treating the new loan’s total interest alone as a complete refinance analysis.

Common Limits and Input Problems

Monthly savings must be a positive estimate in this calculator. If the proposed payment is higher, this particular break-even formula does not apply; compare full payment and cost schedules instead. The savings input is supplied by the reader and is not derived from current and proposed mortgage details, so an inaccurate estimate produces an inaccurate break-even result.

• Do not confuse the amount borrowed with the home’s value or the payoff amount.
• Do not count the same fee twice—for example, both in the loan amount and in estimated costs—unless the comparison is intentionally tracking both borrowing and cash charges.
• Do not interpret the monthly payment as the complete housing payment. Taxes, insurance, and other items can be separate.
• Small differences from another calculator can come from rounding, payment timing, or whether fees are financed. This tool rounds the monthly payment to cents before calculating total interest.

Ask the lender for the exact proposed payment, costs, APR, and loan terms before relying on an estimate. The calculator does not model every contract detail, and it cannot account for future changes in expenses or how long a borrower keeps the loan.

Frequently Asked Questions

What does a home refinance cost calculator compare?
It can estimate a proposed loan’s payment and interest, then compare estimated one-time costs with estimated monthly savings. The result depends on the inputs and on what the calculator includes.

How do I calculate a refinance break-even point?
Divide estimated one-time costs by estimated monthly savings. For example, $6,000 ÷ $100 per month equals 60 months. This simple method assumes savings stay constant and excludes other cash-flow differences.

Does a lower monthly payment mean refinancing costs less?
Not necessarily. A longer repayment term can lower the scheduled payment while extending the time interest accrues. Compare the payment, costs, term, and projected payments over the period being considered.

Should refinance costs be included in the new loan amount?
Use the loan amount shown in the proposed terms. If costs are financed, they generally form part of the amount borrowed in the estimate; do not also treat them as an upfront cash cost without accounting for the distinction.

Why does this calculator ask me to enter monthly savings?
The calculator does not know the current mortgage’s balance, rate, remaining term, or payment. Entering a savings estimate lets it compute a simple cost break-even period, but that estimate should be checked against comparable loan figures.

This result is an estimate, and the lender’s disclosure gives the exact figures.

Related

• Escrow Deposit Calculator: Estimate Your Upfront Deposit
• Escrow Cushion Calculator: Estimate the Required Reserve
• Escrow Closing Date Calculator: Estimate Your Closing

in p | New loan amount | $ | 300000 | 1 | 100000000
in apr | Interest rate (APR) | % | 6.5 | 0.01 | 100
in yrs | New loan term | years | 30 | 0.0833 | 50
in cost | Estimated refinance costs | $ | 6000 | 0 | 10000000
in save | Estimated monthly savings | $ | 100 | 0 | 1000000
out pmt | New monthly principal and interest | $ | round(p * (apr / 1200) / (1 - (1 + apr / 1200) ^ -(yrs * 12)), 2) | 2
out int | Total interest over new term | $ | pmt * yrs * 12 - p | 2
out breakeven | Cost break-even time | months | cost / save + 0 * sqrt(save) | 1