Personal Loan Payment Calculator and Rate Comparison

This personal loan calculator estimates the monthly payment and total interest for a fixed-rate loan from its amount, annual percentage rate (APR), and term. To compare loans, enter each lender’s quoted APR and term alongside the same loan amount; the results show how those assumptions change the payment and interest.

Formula

The calculator uses the standard fixed-payment amortization formula. Monthly payment = P × r / (1 − (1 + r)⁻ⁿ). Total interest = (monthly payment × n) − P.

• P is the loan amount in dollars.
• APR is the annual percentage rate entered as a percentage, such as 8 for 8%.
• r is the monthly rate, calculated as APR ÷ 1,200.
• n is the number of monthly payments, calculated as years × 12.

The displayed payment is rounded to the nearest cent. Total interest uses that rounded monthly payment multiplied by the number of payments, then subtracts the original loan amount. The APR entry is treated as a nominal annual rate divided monthly; this is a calculation convention, not a substitute for a lender’s quoted payment schedule or disclosures.

Worked Example

Using the calculator’s default inputs: loan amount P = $20,000, APR = 8%, and term = 5 years.

1. Convert the annual rate to a monthly rate: r = 8 ÷ 1,200 = 0.0066667.
2. Convert the term to monthly payments: n = 5 × 12 = 60.
3. Apply the payment formula: $20,000 × 0.0066667 ÷ [1 − (1.0066667)⁻⁶⁰] = $405.53 per month, rounded to cents.
4. Calculate total interest using the rounded payment: ($405.53 × 60) − $20,000 = $4,331.80.

Assumptions

• The APR is fixed for the full term.
• Payments are equal, made monthly, with the first payment one month after borrowing.
• Interest accrues monthly using APR ÷ 12.
• Fees, taxes, insurance, and other charges are not included. Any lender-specific fee treatment must be checked in the lender’s disclosures.

How to Compare Personal Loan Rates

A rate comparison is meaningful only when the offers are lined up on comparable terms. Keep the requested amount and repayment period the same when comparing estimated payments. If one offer has a shorter term, its monthly payment may be higher even if its APR is lower; a longer term can lower the payment while increasing the number of payments and potentially the total interest.

For each offer, use the APR and term shown in the lender’s actual quote or disclosure. APR is intended to reflect the interest rate and certain costs of borrowing, but the way a particular offer presents fees and repayment details matters. Check whether the quoted amount is the amount you receive or the amount before any deductions, and whether fees are paid separately or included in the loan balance. This calculator has no fee input, so it cannot reproduce a quote that incorporates such details.

• Compare the same principal amount and term first.
• Record the quoted APR, payment, number of payments, and total amount due from each lender’s disclosure.
• Check whether the rate is fixed or variable and whether the offer includes charges not represented in this estimate.
• Use the calculator’s result as a common arithmetic baseline, not as a prediction of approval or a lender’s final terms.

Reading the Results and Common Mistakes

The monthly payment is the estimated scheduled amount under the formula’s assumptions. Total interest is an estimate of the interest paid over all scheduled payments; it is not the total amount repaid. Add the principal to total interest to see the modeled repayment amount, which here is $24,331.80. A lender’s actual schedule can differ because of fees, payment dates, rounding conventions, or other terms.

A frequent comparison mistake is focusing only on the payment. For example, a smaller payment on a longer term does not by itself mean borrowing costs less: the loan remains outstanding for more months. Another mistake is entering an interest rate as a decimal. Enter 8 for 8%, not 0.08. The APR field accepts values from 0.01% to 100%; actual quoted figures should be entered as provided by the lender.

Rounding also matters. This calculator rounds the monthly payment to cents and calculates interest from that rounded figure. A lender may calculate interest daily or use a different payment schedule, producing a small difference. The formula does not model early payoff, extra payments, late payments, a changing rate, or a balance that changes through refinancing.

What This Calculator Cannot Tell You

The estimate cannot show whether a lender will approve an application, what APR or fee it will offer, or how a particular borrower’s circumstances affect an offer. It also cannot decide which loan fits someone’s needs. Those questions depend on lender-specific information and the complete terms supplied for an offer.

To check an offer, compare the calculator’s estimate with the payment schedule and disclosures supplied by the lender. If the numbers differ, look for differences in the amount financed, fees, rate basis, payment dates, or term rather than assuming the calculator captures every contract detail. This is estimate arithmetic for education, not financial advice. The result is an estimate, and the lender’s disclosure gives the exact figures.

Frequently Asked Questions

How do I compare personal loan rates?
Enter the same loan amount and term for each quoted APR, then compare the estimated payment and interest. Also review each lender’s disclosed fees, repayment schedule, and total amount due; this calculator does not model every offer detail.

Is APR the same as the interest rate?
They are related but not necessarily identical. APR can include certain borrowing costs as well as interest, while the exact calculation and fee treatment depend on the offer. Use the APR stated in the lender’s disclosure and read the accompanying terms.

Why is a loan with a lower payment not always cheaper?
A longer repayment term generally means more monthly payments. Even if each payment is smaller, the total interest can be higher. Compare the term and total repayment as well as the payment amount.

Does this calculator include loan fees?
No. It uses the entered amount, APR, and term only. Fees may affect the amount received, amount financed, APR, or total repayment; check the lender’s disclosure for how any fee applies.

Can I use this calculator for a variable-rate loan?
It provides a fixed-rate estimate. It cannot predict future rate changes or payments on a variable-rate loan. Use the lender’s schedule and terms to understand how a changing rate may affect payments.

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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