Car loan payment formula
Negative trade-in equity should be added to the next loan rather than entered as positive equity.
A standard amortising payment applies the monthly interest rate to the declining balance over a fixed number of payments. The result is an estimate: payment dates, lender fees, precomputed-interest contracts and optional products can change the written figure.
Why compare 48, 60 and 72 months?
The shortest affordable term normally produces less total interest. A longer term can make the payment look easier while leaving the loan outstanding for more of the vehicle’s life. Run the same principal and APR at several terms, then compare total interest rather than the payment alone.
Verify these numbers before signing
Ask for the vehicle price, amount financed, APR, finance charge, payment count, monthly payment and total of payments in writing. Confirm whether the loan uses simple or precomputed interest and how extra payments are applied. Do not let an optional add-on disappear inside the payment.
If the vehicle’s complete monthly cost is close to your limit, check it with the car affordability calculator before choosing a term.
The $500 car payment example shows why the written payment should be placed inside the complete vehicle budget before comparing it with income.
Sources and checks
AutoPrisme uses the figures you enter. The links below explain the rule, market context or consumer protections used to frame this calculator. Always verify the numbers in your own quote or contract.
- Consumer Financial Protection Bureau — Comparing auto-loan offersOfficial US guidance on amount financed, APR, loan length, monthly payment and total interest.
- Consumer Financial Protection Bureau — Truth-in-Lending disclosureExplains APR, finance charge, amount financed, monthly payment and total of payments.
- Federal Trade Commission — Financing or leasing a carConsumer guidance on total cost, down payments, add-ons and comparing written finance offers.
Frequently asked questions
How is a monthly car loan payment calculated?
For a standard amortising loan, the payment depends on the amount financed, monthly interest rate and number of monthly payments. A zero-interest loan simply divides the principal by the term.
Should taxes and dealer fees be included in the loan?
Include every tax, fee or add-on that will actually be financed. Keep cash paid at signing separate so the amount financed matches the written contract.
Is APR the same as the interest rate?
Not always. APR is designed to express the yearly cost of credit and may include mandatory finance fees. Compare APR with APR and verify the lender's disclosure before signing.
Why can a longer loan cost more with a lower payment?
Spreading the principal over more months can reduce each payment, but interest accrues for longer. Compare the total interest and total of payments, not only the monthly figure.