Personal Loan Refinance Rates: Compare the True Cost

This personal loan refinance calculator estimates the monthly payment and total interest for a replacement loan from its amount, APR, and term; it does not compare live lender rates. Enter the new loan’s figures to see the scheduled payment and interest, then compare those estimates with your existing loan and any fees using quotes from lenders.

Formula

The calculator uses the standard fixed-rate, fully amortizing loan payment formula. It converts the annual percentage rate (APR) to a monthly rate and spreads repayment over the number of monthly payments:

Monthly payment = round[P × r ÷ (1 − (1 + r)⁻ⁿ), 2]

• P is the replacement loan principal, in dollars. The amount entered should reflect the balance being refinanced plus any amount financed into the new loan, if applicable.
• r is the monthly interest rate, calculated as APR ÷ 1,200. For an APR of 8%, for example, r is 0.08 ÷ 12.
• n is the number of monthly payments, calculated as the term in years × 12.
• APR is entered as a percentage per year, not as a decimal. The displayed payment is rounded to the nearest cent.

Total interest is estimated as the rounded monthly payment multiplied by the number of payments, minus the principal: Total interest = monthly payment × n − P. This method uses the rounded payment for the total, so the arithmetic agrees with the payment shown. Actual lender schedules can differ because of payment dates, rounding practices, and loan-specific charges.

Worked Example

Using the calculator’s default values—$20,000 principal, 8% APR, and a five-year term—there are 5 × 12 = 60 monthly payments. The monthly rate is 8 ÷ 1,200 = 0.0066667.

Substituting into the payment formula gives:

$20,000 × 0.0066667 ÷ [1 − (1 + 0.0066667)⁻⁶⁰] = $405.53 per month, rounded to cents.

Using that displayed payment, estimated total interest is $405.53 × 60 − $20,000 = $4,331.80. The scheduled payments total $24,331.80, of which $20,000 repays principal and $4,331.80 is estimated interest.

Assumptions

• The APR stays fixed for the entire term.
• Payments are equal, made monthly, and begin on schedule; the model does not account for unusual first or final payment dates.
• Interest is compounded monthly using APR ÷ 12 as the periodic rate.
• Fees, taxes, insurance, and other charges are not included. Any fee added to the loan balance must be reflected in the principal input to be represented in the estimate.

How to Compare Refinance Rates

A refinance-rate comparison is meaningful only when the offers are evaluated on comparable terms. A lower APR can reduce interest for the same balance and term, but changing the term changes both the payment and the length of time interest accrues. The calculator does not retrieve or verify offers: obtain the actual APR, payment schedule, amount financed, and charges from each lender’s written quote or disclosure.

For a useful side-by-side comparison, record for each offer:

• The amount that will actually be borrowed, including any financed charges.
• The APR and whether it is fixed for the full repayment period.
• The repayment term, monthly payment, and total scheduled payments.
• Origination or other charges, whether paid upfront or included in the balance, and any conditions that affect the quote.
• The existing loan’s payoff amount and remaining payment schedule, obtained from its servicer.

Compare total costs over the same period and include charges that the calculator omits. If the new loan is smaller than the amount needed to repay the old one, extra cash may be required; if a fee is financed, it increases the balance and can also accrue interest.

Reading the Results and Understanding Trade-Offs

The monthly payment is the scheduled amount under the formula’s assumptions, not a guarantee of what a lender will quote or collect. The total-interest figure estimates interest across all scheduled payments. It does not include fees, and it assumes every payment is made as planned with no early payoff or payment changes.

A longer term generally spreads repayment across more months, which can reduce the required monthly payment while increasing total interest at the same rate and principal. Conversely, a shorter term can raise the payment even if it reduces the time interest accrues. Therefore, comparing monthly payments alone can obscure the total cost. For an apples-to-apples calculation, compare offers using the same loan amount and term, then separately examine the terms and charges each quote actually sets out.

Also distinguish the APR from the interest rate. APR is a standardized annualized cost measure, but the exact items included in a lender’s APR and the way charges are presented depend on the loan disclosure. Use the disclosed APR for the calculator’s rate input, and review the quoted payment and total repayment figures directly rather than assuming this simplified formula captures every charge.

Common Comparison Problems and Limits

One frequent mistake is entering the current loan balance when the new loan would need to cover a larger payoff amount or financed charges. Another is comparing a new loan’s payment with the old loan’s payment without accounting for different terms or remaining months. A smaller payment may reflect a longer repayment period, not a lower overall cost.

The estimate also cannot determine whether a lender will approve an application, what rate an individual will receive, or whether an offer fits someone’s circumstances. It does not model variable rates, late payments, extra principal payments, a changing balance, promotional terms, or exact daily-interest calculations. Its 0.01% minimum APR avoids a zero-rate division in the formula; it is a calculation boundary, not a statement about available offers.

Frequently Asked Questions

Does refinancing a personal loan always lower the interest rate?
No. A replacement loan’s APR depends on its actual terms and quote. Compare disclosed figures rather than assuming refinancing produces a lower rate.

Can a lower monthly payment cost more overall?
Yes. A longer term can lower the scheduled monthly payment while extending repayment and increasing total interest. Compare total payments and charges as well as the monthly amount.

Should I include refinance fees in the loan amount?
If a fee is added to the new balance, include it in the principal input for a closer payment estimate. If it is paid upfront, the calculator will not include it, so account for it separately when comparing total costs.

Why does the calculator’s result differ from a lender quote?
The estimate excludes charges and detailed payment-date calculations, and it assumes a fixed rate with equal monthly payments. A lender’s disclosure and repayment schedule use the loan’s specific terms and give the relevant figures.

Can I use the calculator to find the rate I qualify for?
No. It calculates payment and interest from an APR you enter; it cannot determine an offered or approved rate. Request actual terms from the lender.

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

Related

• Why Is My Student Loan Balance Zero?
• Xero Entity Loan Balance: Where to Find It
• Y Balance Test Calculator: Meaning and Formula

in p | Loan amount | $ | 20000 | 1 | 100000000
in apr | Interest rate (APR) | % | 8 | 0.01 | 100
in yrs | Loan term | years | 5 | 0.0833 | 50
out pmt | Monthly payment | $ | round(p * (apr / 1200) / (1 - (1 + apr / 1200) ^ -(yrs * 12)), 2) | 2
out int | Total interest | $ | pmt * yrs * 12 - p | 2