Auto Loan Calculator with Trade-In, Tax & Fees

How to use this calculator

This auto loan calculator with trade-in and sales tax shows your real monthly payment, not just the sticker math. Enter what you know from the dealer's offer or your preapproval.

• Vehicle price: the negotiated price before tax and fees.
• New or used: sets a starting APR from Experian's Q2 2026 averages, 6.35% for new and 11.19% for used. Replace it with your actual quote.
• APR and loan length: pick 36, 48, 60, 72 or 84 months.
• Down payment: cash you put down at signing.
• Trade-in value and amount owed: what the dealer offers for your car and the payoff on its loan.
• State: sets the vehicle tax rate and whether your trade-in lowers the taxable price. You can also enter your own rate.
• Fees: title, registration and dealer documentation fees.
• Finance tax and fees: rolls them into the loan instead of paying cash.
• Rebates: cash incentives from the manufacturer or dealer.

You'll see the monthly payment, amount financed, total interest, first-year interest and total cost. A table compares every loan length side by side. If you owe more on your trade-in than it's worth, a warning shows how much negative equity you're rolling in.

How we calculate your car payment

Taxable price = price − trade-in value  (if your state credits trade-ins)
              = price                   (if it doesn't)
Sales tax = taxable price × tax rate

Trade equity = trade-in value − amount owed  (negative = negative equity)

Amount financed = price − rebates − down payment − trade equity
                  + sales tax + fees  (if you finance them)

Monthly payment = L × r ÷ (1 − (1 + r)^−n)
  L = amount financed, r = APR ÷ 12, n = months

Worked example: a $35,000 new car with $4,000 down, 7% sales tax, $800 in fees financed, and 6.35% APR for 60 months. No trade-in.

Car payment by loan length: 60 vs 72 month car loan

The calculator compares every term on the same amount financed. For the $34,250 example at 6.35%:

Going from 60 to 72 months lowers the payment by about $95. It also adds about $1,200 in interest. Lenders often charge higher APRs on longer terms, so the real gap may be bigger than this table shows.

Longer loans carry another risk. Cars lose value fastest in the first few years. With a small down payment and a long term, you can owe more than the car is worth for much of the loan. That matters if the car is totaled or you want to trade it in early.

Trade-ins, sales tax and negative equity

How trade-ins affect tax: most states tax only the difference between the price and your trade-in. That's a real saving. A $10,000 trade-in at 7% tax cuts the tax bill by $700.

A few places tax the full price no matter what you trade in. These include California, Virginia, Oklahoma, Hawaii and DC. Kentucky does the same on new cars. Some states also use special vehicle taxes instead of sales tax, or cap the credit. Michigan, for example, limits the trade-in credit to $12,000 in 2026. Choose your state and the calculator applies its rule.

Negative equity: say you trade in a car worth $10,000 but still owe $13,000 on it. That $3,000 gap gets added to your new loan.

The tax credit helps a little, but you're still financing $3,000 for a car you no longer own. In a state with no trade-in credit, the tax stays at $2,450. The loan rises to $37,250, and the payment to about $726.

If you have negative equity, consider paying it down before you buy, putting more cash down, or keeping your current car longer.

Car loan interest deduction

For tax years 2025 through 2028, you may be able to deduct up to $10,000 a year of interest on a car loan. The vehicle must be new, assembled in the US, bought after 2024 and used for personal purposes. The deduction phases out above $100,000 of modified adjusted gross income, or $200,000 for joint filers.

In the example above, first-year interest is about $2,002. That's the figure the calculator shows, so you can estimate what might qualify. The deduction lowers taxable income, not your tax bill dollar for dollar. Used cars and leases don't qualify. See the IRS guidance for details.

The 20/4/10 rule and other guardrails

The 20/4/10 rule is a conservative way to keep a car affordable:

• 20% down, to avoid owing more than the car is worth.
• 4 years or less of financing.
• 10% or less of gross income on total car costs, including payment, insurance and fuel.

On a $35,000 car, 20% down is $7,000. A 48-month loan keeps interest low. On $100,000 of gross income, 10% is about $833 a month for everything. Few buyers hit all three, but each one you meet lowers your risk.

A few more tips:

• Get preapproved first. A bank or credit union offer gives you a rate to beat at the dealer.
• Negotiate the price, not the payment. A dealer can hit any monthly number by stretching the term.
• Watch add-ons. Extended warranties, GAP coverage and other extras are often rolled into the loan.

Used car loan rates

Used-car loans typically carry higher rates. At Experian's 11.19% average, the same $34,250 for 60 months would cost about $748 a month and $10,626 in interest. That's $4,800 more than at the new-car average. A lower price can still make a used car cheaper overall, so compare total cost, not just APR.

If a car loan is part of a bigger budget, see how it fits with your paycheck calculator results. If you're juggling several debts, the debt snowball vs avalanche calculator shows which to pay off first. For other borrowing, try the personal loan calculator.