Loan APR Calculator
Find the interest rate implied by a loan payment, or estimate APR when fees are paid at closing, with total interest and total finance charge.
Interactive calculator · Method LOAN-APR-1.0 · Last reviewed: 2026-11-04
Calculate your scenario
Payment M = P × r ÷ (1 − (1 + r)^−n), with r = annual rate ÷ 12 ÷ 100 and n = months (M = P ÷ n at 0%).
Your inputs
Default worked example. Edit the inputs to calculate your scenario.
Default worked example
60 payments of $396.02 repay $20,000.00 at a 7% note rate; the same payments on the $19,500.00 you receive after fees imply an APR of about 8.068%.
How to use the calculator
Choose what you know. With a note rate and fees, enter the loan amount, term, rate and closing fees as a percent of the loan. With only a payment, enter the payment, term and loan amount to solve the note rate; any fee percentage then turns that into an APR estimate.
What the result means
A $20,000, 60-month loan at a 7% note rate costs $396.02 a month; if $500 of fees come out at closing, those same payments on $19,500 work out to an APR of about 8.07%.
Formula and units
Payment M = P × r ÷ (1 − (1 + r)^−n), with r = annual rate ÷ 12 ÷ 100 and n = months (M = P ÷ n at 0%). In payment mode the note rate is the r that makes this formula equal your payment on the loan amount, found by bisection. Estimated APR = 12 × the monthly rate at which the same payment repays only the amount you receive (loan amount − prepaid finance charges). Total interest = M × n − loan amount; total finance charge = total interest + prepaid finance charges.
Worked examples
$20,000 at 7% for 60 months with 2.5% fees: Term: 60 months; Monthly payment (payment mode): 400 USD; Loan amount (note amount): 20000 USD; Note interest rate (rate-and-fees mode): 7 % per year; Prepaid finance charges paid at closing: 2.5 % of loan amount; What you know: fees.
Example result: Estimated APR: 8.068%; Note rate: 7% (entered); Monthly payment: $396.02 (calculated); Total interest: $3,761.44; Prepaid finance charges: $500.00 (2.5% of loan); Total finance charge: $4,261.44.
$25,000 repaid at $600 a month for 48 months: Term: 48 months; Monthly payment (payment mode): 600 USD; Loan amount (note amount): 25000 USD; Note interest rate (rate-and-fees mode): 7 % per year; Prepaid finance charges paid at closing: 0 % of loan amount; What you know: solve.
Example result: Estimated APR: 7.116%; Note rate: 7.116% (solved from the payment); Monthly payment: $600.00 (entered); Total interest: $3,800.00; Prepaid finance charges: $0.00 (0% of loan); Total finance charge: $3,800.00.
Limitations and common mistakes
An actuarial-method estimate for a fixed-rate, level-payment loan with fees paid at closing; it is not a Truth in Lending disclosure. Which fees count as finance charges, odd first periods, rounding of payments and add-on products follow regulatory rules this page does not apply. Rates and fees are figures you enter; nothing here is a quoted or market rate, and the defaults are only examples.
Treating the note rate as the APR. Fees paid at closing mean you receive less than you repay on, so the true yearly cost is higher than the note rate.
Sources and assumptions
Method LOAN-APR-1.0; last formula review 2026-11-04. Sources and their supported claims. Calculation methodology.