How is the monthly auto loan payment calculated?

The calculator uses the amortizing loan formula PMT = P · i / (1 - (1 + i)^-n), where P is the amount financed, i is the monthly interest rate (APR/12), and n is the number of months.

Does sales tax apply before or after the down payment?

This varies by jurisdiction. Many regions tax Price minus Trade-in, while others tax after down payment as well. Choose the tax base that matches your local rules or consult your DMV.

Can I finance fees and taxes?

Yes. The calculator adds selected fees and applicable taxes to the amount financed unless you pay them upfront via a larger down payment.

When APR is 0, the monthly payment equals Amount Financed divided by the number of months, with no interest charged.

Is the output a quote or financial advice?

No. Results are estimates for planning. Rates, taxes, and fees vary. Always confirm with your lender and local authorities.

Auto Loan Calculator

Estimate your monthly car payment, amount financed, total interest, and overall cost. Ideal for car buyers, auto dealers, and financial planners seeking a precise, accessible, and mobile-first tool.

Loan Inputs

Vehicle price ($) *

Down payment *

Amount Percent

Sales tax rate (%)

Tax fees

APR (% yearly) *

Loan term *

Months Years

Results

Amount financed $0.00

Monthly payment $0.00

Total interest $0.00

Total of payments $0.00

Estimated sales tax $0.00

APR 0.00%

Term 0 months

Assumptions: fixed-rate amortizing loan with equal monthly payments. Results are estimates and may differ from lender offers.

The Formula Explained

Monthly payment (amortizing loan): $ \mathrm{PMT}=\dfrac{P \cdot i}{1-(1+i)^{-n}} $

where $ P $ is amount financed, $ i=\text{APR}/12 $, $ n $ is months. For APR $ =0 $: $ \mathrm{PMT}=P/n $.

Amount financed with taxes and fees: $ P=(\text{Price}-\text{Down}-\text{TradeIn})+\text{Fees}+\text{Tax}_{\text{sales}} $.

Data Source and Methodology

Authoritative source: OpenStax, “Business Math,” Section 13.3 Annuities—Present Value and Payments, 2022. openstax.org.

All calculations are strictly based on the formulas and data provided by this source.

Tool developed by Ugo Candido. Content verified by the CalcDomain Expert Review Team.
Last reviewed for accuracy on: 2025-09-12.