Home Refinance Costs: Estimate Your New Payment

Home refinance costs depend on the new loan amount, interest rate, term, and lender fees; there is no single price or rate that applies to every borrower. This calculator estimates the monthly principal-and-interest payment and total interest from the loan amount, APR, and term you enter; it does not calculate closing costs or determine whether refinancing saves money.

Formula

The calculator uses the standard fixed-rate, fully amortizing loan payment formula:

Payment = P × r ÷ [1 − (1 + r)⁻ⁿ]

• P is the new loan principal, in dollars.
• r is the monthly interest rate, calculated as annual APR ÷ 1,200. For example, 6.5% gives a monthly rate of 0.065 ÷ 12.
• n is the number of monthly payments: years × 12.
• Payment is the monthly principal-and-interest amount, rounded to cents.

Total interest is the rounded monthly payment multiplied by the number of payments, minus the starting principal: Interest = Payment × n − P. APR and the loan amount must be figures supplied for the refinance you are evaluating; the default APR is only an example input, not a current-rate claim.

Worked Example

Using the calculator’s default inputs—$300,000, 6.5% APR, and 30 years:

1. Convert the annual rate to a monthly decimal: 6.5 ÷ 1,200 = 0.0054166667.
2. Find the number of payments: 30 × 12 = 360.
3. Substitute into the payment formula: $300,000 × 0.0054166667 ÷ [1 − (1.0054166667)⁻³⁶⁰] = approximately $1,896.20 per month.
4. Calculate total interest using the payment rounded to cents: $1,896.20 × 360 − $300,000 = $382,632.00.

The payment is for principal and interest only. A real monthly mortgage bill may also include taxes, insurance, mortgage insurance, or escrow items, which are not estimated here.

Assumptions

• The interest rate is fixed for the full term.
• Payments are equal monthly payments made at the end of each monthly period.
• Interest accrues monthly at APR ÷ 12.
• The estimate excludes lender and third-party fees, taxes, insurance, mortgage insurance, escrow, and any existing-loan payoff charges.

What Home Refinance Costs Include

“Refinance cost” can mean either the new monthly payment or the one-time expense of replacing an existing mortgage. The calculator gives the payment and scheduled interest, not the cash needed to close. A refinance may involve lender charges and services associated with valuing, documenting, or closing the transaction. The exact items and amounts depend on the loan and transaction, so obtain an itemized estimate from the lender rather than assuming a standard fee.

Also distinguish costs paid at closing from costs added to the new principal. If charges are financed, the new loan amount is larger and the payment and total interest can rise. A lender may present a loan with no separately billed closing costs, but that does not establish that the costs disappear; ask how the arrangement affects the rate, principal, and overall figures. Do not enter the old mortgage balance alone if the proposed new principal includes financed charges or other amounts.

How to Use the Estimate

Enter the proposed refinance principal, the APR quoted for the specific loan scenario, and the repayment term. For an approximate payment comparison, use the same assumptions for each scenario and change one input at a time. The result is useful for seeing how term, loan size, or rate changes the scheduled principal-and-interest payment. It is not a lender quote, approval decision, or complete household budget.

To evaluate the full transaction, compare the new loan’s payment and total scheduled interest with the existing loan’s remaining payments, while separately accounting for closing costs and any change in the time until payoff. A lower monthly payment by itself does not prove that the transaction costs less overall: extending repayment can reduce the monthly amount while increasing the number of months interest accrues. Conversely, a shorter term can increase the payment even when the total repayment period is reduced.

Common Comparisons and Limitations

Compare like with like. A meaningful payment comparison needs the proposed principal, APR, and term for each scenario. It should also identify whether the loan is fixed-rate or variable-rate; this calculator assumes fixed rate and cannot model a rate that changes. It does not calculate cash-out proceeds, lender fees, prepaid items, taxes, insurance, payoff timing, or the balance on the old loan.

• Payment versus total interest: The monthly result is not the total cost of borrowing. Read it alongside total interest and the term.
• APR versus note rate: APR is an annualized disclosure measure that can reflect certain costs; the contract’s interest rate is used to accrue interest. For a precise payment estimate, use the rate that applies to the payment calculation and review the lender’s disclosed APR and fees separately.
• Rounding: The displayed payment is rounded to cents. A lender’s schedule can differ slightly because of exact dates, rounding conventions, or servicing details.
• Break-even: A simple break-even estimate divides eligible upfront costs by monthly payment reduction, but it can omit term changes, financed fees, and future loan balance differences. It is not a complete comparison.

Get the actual loan terms and itemized charges directly from the lender. If the quoted APR, principal, or term changes, the calculator’s result changes too.

Frequently Asked Questions

How much does it cost to refinance a home?
There is no universal amount. Costs depend on the particular transaction and may include lender and third-party charges or prepaid items. Request an itemized estimate; this calculator does not total those charges.

Does refinancing lower the monthly payment?
It can, but it is not guaranteed. The result depends on the new principal, APR, and term. A longer repayment term can lower the payment while increasing the time interest is paid.

Are refinance closing costs included in the calculator?
No. It estimates principal and interest from the inputs only. Add any fees financed into the loan to the principal input to see their approximate payment effect, but that still does not calculate all closing costs.

What information do I need for an accurate estimate?
Use the proposed loan amount, the applicable rate or APR as appropriate to the calculation, and the term. For a complete cost comparison, also obtain itemized transaction charges and the existing loan’s remaining balance and payment schedule.

Why can total interest rise when the payment falls?
A longer term spreads repayment across more months. Even if each payment is smaller, interest can accrue for longer, so compare both payment and total interest rather than relying on the monthly figure alone.

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

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• APR and EAR Calculator: Compare Annual Interest Rates

in p | New loan amount | $ | 300000 | 1 | 100000000
in apr | Interest rate (APR) | % | 6.5 | 0.01 | 100
in yrs | Loan term | years | 30 | 0.0833 | 50
out pmt | Monthly principal-and-interest payment | $ | p * (apr / 1200) / (1 - (1 + apr / 1200) ^ -(yrs * 12)) | 2
out int | Total interest over term | $ | pmt * yrs * 12 - p | 2