Refinance a High-Interest Personal Loan? Compare Payments

This calculator estimates the monthly payment and total interest on a fixed-rate personal loan from its amount, APR, and term. Enter the proposed loan terms to see the scheduled payment and interest; it does not decide whether refinancing is appropriate or include lender fees.

Formula

The calculator uses the standard fixed-payment amortization formula. Let P be the loan principal in dollars, a the APR in percent per year, r = a / 1200 the monthly interest rate as a decimal, and n = 12 × years the number of monthly payments. The payment before display rounding is:

M = P × r / [1 − (1 + r)⁻ⁿ]

The calculator rounds the monthly payment, M, to the nearest cent. It estimates total interest as (rounded M × n) − P. The APR and term must describe the proposed replacement loan for a refinance comparison. The formula assumes one fixed rate and equal monthly payments; it does not calculate a payoff quote for the existing loan.

Worked Example

Using the defaults—$20,000 principal, 8% APR, and five years:

• Monthly rate: 8 ÷ 1,200 = 0.0066667.
• Number of payments: 5 × 12 = 60.
• Payment: $20,000 × 0.0066667 ÷ [1 − (1.0066667)⁻⁶⁰] = about $405.53 per month, rounded to cents.
• Total of scheduled payments: $405.53 × 60 = $24,331.80.
• Estimated total interest: $24,331.80 − $20,000 = $4,331.80.

Assumptions

• The APR is fixed for the full term, with monthly payments made at the end of each period.
• Interest is compounded monthly at APR divided by 12.
• The calculation excludes origination or other fees, taxes, insurance, and any charges not entered as loan principal.
• It assumes the full amount entered is borrowed and that each scheduled payment is made on time.

What Refinancing a Personal Loan Means

Refinancing means taking out a new loan to pay off an existing one. The replacement loan may have a different APR, term, payment, or amount. The borrower then repays the new loan according to its contract. This calculator models the replacement loan’s scheduled payment and interest, not the complete transaction.

A lower monthly payment alone does not show that refinancing reduces borrowing costs. The new term could be longer, so payments may continue for more months and total interest may rise. Conversely, a shorter term can raise the monthly payment even if the scheduled interest is lower. A fair comparison needs the remaining balance and payoff amount on the current loan, its remaining payment schedule, and the new loan’s written terms and costs.

How to Compare a Refinance

Use the replacement loan’s actual principal, APR, and term from its disclosure or offer, rather than an advertised starting figure. The amount borrowed may differ from the current balance if fees are added or if the borrower requests extra cash. Check whether the lender pays the old creditor directly or whether the borrower must arrange payoff, and confirm the old account is settled.

1. Request the current loan’s payoff amount for the date the new loan would fund. A payoff quote can differ from the statement balance because of accrued interest or other contract amounts.
2. Collect the new loan’s APR, term, payment, amount financed, and itemized fees. Ask how fees are paid and whether they are included in the principal.
3. Compare the remaining scheduled payments on the existing loan with the replacement loan’s total scheduled payments plus costs paid separately. Keep the comparison period and assumptions clear.
4. Review the contract for prepayment charges, payment dates, late-payment terms, and any optional products or services. This calculator does not model those terms.

For example, suppose a current loan has 24 payments remaining at $500 each. Those scheduled payments total $12,000, but that figure is not necessarily the amount required to pay it off today. A proposed replacement loan could show a lower monthly payment by extending repayment beyond two years. Compare its full scheduled payments and costs with the current loan’s actual remaining obligations—not just $500 against the new payment.

Costs, Trade-Offs, and Common Problems

APR is useful for comparing borrowing costs, but the calculator cannot determine whether an APR includes every charge or how a particular lender presents fees. An origination fee paid from the proceeds can mean the borrower receives less cash than the stated principal. If a fee is added to the balance, interest may accrue on it too. Include such costs in a separate comparison instead of treating the displayed interest as the entire cost of refinancing.

Other common comparison errors include using the original loan amount instead of its current payoff amount, comparing different repayment periods, and assuming that a lower payment guarantees lower total cost. Payment dates and payoff timing also matter: interest can accrue between a quote and the date funds arrive. Obtain figures for the expected funding date and check whether there are charges for paying the existing loan early.

Refinancing does not erase debt; it replaces one obligation with another. If the new balance includes extra borrowing, the payment and interest calculation applies to that larger amount. A personal loan may also have contract terms or payment arrangements that this basic formula cannot represent. Read the documents and verify the payoff rather than relying on an estimate alone.

What This Calculator Does Not Show

This is a fixed-rate estimate. It does not check eligibility, predict an approval decision, determine a rate, or account for lender-specific underwriting. It also does not model variable rates, irregular payments, skipped or late payments, payment changes, daily interest, or a changing balance caused by additional borrowing. The minimum APR in the input prevents a zero-rate calculation; use a lender’s figures and disclosures for the specific transaction.

Rounding the payment to cents can make the final payment differ slightly from earlier payments, depending on the lender’s schedule. The calculator multiplies the rounded payment by the full number of months for its total-interest estimate. Actual statements and payoff figures can vary because of payment timing, rounding, fees, and contract details.

Frequently Asked Questions

Does refinancing a personal loan lower the monthly payment?
A new loan’s payment depends on its principal, APR, and term. A longer term can lower the scheduled payment while increasing the number of payments; compare the full costs as well as the monthly amount.

Does a lower APR always mean paying less overall?
No. The new term, financed fees, and amount borrowed also affect total payments. Compare the remaining cost of the existing loan with all payments and costs for the replacement loan.

Can I refinance a personal loan before it is paid off?
Refinancing is generally structured to pay off an outstanding loan, but the lender’s terms and the current contract determine what is possible. Confirm the payoff amount, funding process, and any applicable charges directly with the relevant lenders.

Should I use my current balance or payoff amount?
For a transaction comparison, request a payoff amount dated for the expected payment or funding date. A statement balance may not include interest that accrues before payoff or other amounts specified in the contract.

Does this calculator include refinance fees?
No. It estimates payment and interest for the principal, APR, and term entered. Review the new loan’s itemized costs and account for fees separately, including whether they are paid upfront or added to the balance.

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

Related

• Loan Refinance Calculator: Estimate Monthly Savings
• Loan Refinance Comparison Calculator
• Loan Refinance Break-Even Calculator 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 | $ | p * (apr / 1200) / (1 - (1 + apr / 1200) ^ -(yrs * 12)) | 2
out int | Total interest | $ | pmt * yrs * 12 - p | 2