Auto Loan Calculator
Car payment including sales tax, down payment and trade-in.
Formula
About this calculator
An auto loan calculator answers the question every car buyer really has at the dealership: what will this cost me each month? The monthly payment depends on far more than the sticker price. What you actually finance is the vehicle price plus sales tax, minus your down payment and any trade-in credit — and it's that financed amount, at your interest rate and term, that determines the payment.
Sales tax is the piece buyers most often forget. In most US states, tax is charged on the vehicle's price and rolled into the loan, so a 7% rate on a $35,000 car adds roughly $2,450 to what you borrow. A larger down payment or a valuable trade-in shrinks the financed amount dollar-for-dollar, which lowers both the payment and the total interest you pay.
Loan term is the other big lever. Stretching a loan from 48 to 72 months lowers the monthly payment but raises total interest and increases the risk of being 'underwater' — owing more than the car is worth — because vehicles depreciate faster than the loan is paid down. The amortization schedule below shows exactly how each payment splits between interest and principal over the life of the loan.
Example: a $35,000 vehicle with $5,000 down, no trade-in, 7% sales tax and a 7.5% APR over 5 years finances about $32,450, giving a payment near $650 per month and roughly $6,550 in total interest. Adding a $3,000 trade-in drops the payment by about $60 a month.
Frequently asked questions
Is sales tax included in an auto loan?
In most US states, yes — sales tax is charged on the vehicle price and financed as part of the loan. This calculator adds it to the amount financed so your payment reflects the real out-the-door cost.
Does a trade-in lower my car payment?
Yes. Trade-in value works like extra down payment: it reduces the amount you finance dollar-for-dollar, which lowers both your monthly payment and the total interest paid.
What loan term should I choose?
A shorter term means a higher payment but far less interest and less risk of owing more than the car is worth. Longer terms lower the payment but cost more overall — compare both here before deciding.
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⚠️ Estimates are for general information only and do not include dealer fees, registration, gap insurance or lender-specific charges. Confirm exact figures with your lender or dealer.