How this calculator works
Planning to buy a new or used vehicle? Use our free auto loan calculator to estimate your monthly car payment, total interest expenses, and overall purchase costs. You can enter the vehicle price, down payment, trade-in details, state sales tax, and interest rate to customize your financing options.
- Method
- Fixed-rate, fully amortizing monthly-payment calculation with user-supplied purchase adjustments
- Source
- Consumer Financial Protection Bureau auto-loan guidance and the standard annuity-payment equation
- Last reviewed
- 2026-08-24
Method limitations
- The estimate assumes a fixed rate, equal monthly payments, and no lender-specific daily-interest convention.
- Sales tax is estimated on the full vehicle price; actual trade-in tax treatment varies by jurisdiction.
- User-entered fees, add-ons, and trade-in debt are included in the financed amount; omitted or lender-specific charges remain excluded.
- The entered rate is used as the periodic borrowing rate; a disclosed APR can include fees that this simplified estimate does not model.
- This is an educational estimate, not a lender quote, approval decision, or financial advice.
Engine-backed example
Monthly auto-loan payment: worked example
What is the estimated payment for a $35,000 vehicle with $5,000 down, a $2,000 trade-in, 7% estimated sales tax, and 6% interest for 60 months?
- Vehicle price and upfront reductions
- $35,000, with $5,000 down and a $2,000 trade-in
- Estimated sales tax
- 7% of the full vehicle price
- Rate and term
- 6% for 60 months
Est. Monthly Payment$588.68
- Loan Amount (Principal)
- $30,450.00
- Sales Tax Amount
- $2,450.00
- Total Interest Paid
- $4,871.03
The estimate uses a financed amount of $30,450 and fixed monthly amortization. Actual taxes, fees, add-ons, APR disclosures, and lender conventions can change the payment.
Trust and review
Who created and reviewed this calculator?
- Author
- CalcOS Editorial TeamResponsible for calculator explanations, examples, assumptions, and search-intent clarity.
- Reviewed by
- CalcOS Scientific ReviewTechnical review of fixed-rate amortization, zero-rate handling, purchase adjustments, boundaries, engine parity, and narrative examples; not licensed financial advice.
- Substantive review date
- 2026-08-24Monthly-payment mode, amount financed, supplied sales-tax estimate, down payment, net trade-in equity, financed fees and add-ons, total interest, zero-rate behavior, worked-example parity, and estimate limitations.
Sources
Assumptions used by this calculator
- The loan has a fixed rate and equal monthly payments over the entered term.
- The amount financed is the vehicle price plus estimated sales tax, financed fees/add-ons, and trade-in debt, minus the down payment and trade-in value.
- Sales tax is estimated on the full vehicle price; actual trade-in tax treatment varies by jurisdiction.
- Only fees, add-ons, and trade-in debt entered by the user are included; omitted or lender-specific charges remain excluded.
- The estimate is educational planning information, not a lender quote, approval, or financial advice.