Car loan interest rate calculator
This car loan interest rate calculator finds the interest rate from the loan amount, the monthly payment and the term, so you can check what a quote really costs.
When you need to work out the rate
Sometimes the paperwork shows a payment and a term but the rate is unclear, or a dealer quotes only a payment. Enter the amount financed (after down payment, including tax and fees), the payment and the number of months, and the calculator returns the rate. If it is higher than the rate you were quoted, something extra is in the loan.
Interest rate vs APR
The interest rate is the cost of borrowing the principal. APR includes certain fees, so it is at least as high. If a lender charges loan fees or add-ons financed into the loan, the rate you compute here from the amount financed will not show them separately; include them in the amount.
Why the quoted payment hides the rate
A payment quote can hide a high rate behind a long term. For example, $25,000 financed over 84 months at 6% is $365.21, and the same payment is available at a much higher rate over a shorter term only if you ask. Work out the APR from any quote and compare it with your pre-approval.
Frequently asked questions
How do I find my car loan interest rate?
Check the loan agreement, which must disclose the APR. If you only know the payment, enter the amount, payment and term here.
Why is the rate I calculated higher than the dealer quoted?
Fees, add-ons or a different amount financed than you assumed can raise the effective rate. Ask for the itemized contract.
How do you work out the interest rate from a payment?
There is no closed-form formula, so the calculator searches for the rate at which the payment exactly repays the amount over the term. The result is the rate that accrues monthly on the balance, the same as an APR on a standard installment loan without extra fees.
Why is my rate different from the dealer’s quote?
Fees, add-ons and rounding can raise the effective cost. If the rate you get here is higher than the quoted rate, ask what was added to the amount financed.
Related calculators
Estimates from standard loan formulas, not a loan offer or financial advice. Example rates are assumptions: use your own quote.