Auto Loan Calculator
Calculate your monthly car payment from the vehicle price, down payment, trade-in, sales tax, and fees, or switch to affordability mode to find the vehicle price a target monthly payment supports.
Your monthly payment will appear here
Enter the vehicle price, down payment, and loan terms, then click calculate.
Quick Answer
An auto loan calculator works out your monthly car payment from the vehicle price, down payment, trade-in value, sales tax, fees, interest rate, and loan term. Switch to affordability mode if you'd rather start from a target monthly payment and see what vehicle price fits your budget.
How It Works: Formula & Variables
An auto loan payment gets calculated the same way as any amortized loan, but the loan amount depends on a few car-specific numbers first: take the vehicle price, subtract your down payment and trade-in value, then add sales tax and any fees you decide to roll in.
Loan Amount = Price − Down Payment − Trade-In + Sales Tax + Fees (if rolled in)
- Sales Tax
- Charged on the full vehicle price, or on the price minus your trade-in if your state offers a trade-in tax credit.
- Fees
- One-time title and registration costs, either paid upfront or rolled into the loan (where they then accrue interest).
Worked Examples
Example 1: Buying with a trade-in
A $28,000 vehicle, $5,000 trade-in, $2,000 down payment, 7% sales tax with the trade-in credit applied, $500 in fees rolled into the loan, 6.5% interest, and a 60-month term. The taxable amount drops to $23,000 once the trade-in is subtracted, sales tax comes out to $1,610, and after the down payment and trade-in come off and fees get added back, the loan lands around $18,110.
Example 2: Affordability mode
Say you can comfortably afford $400 a month, with a $3,000 down payment, no trade-in, 6% sales tax, and a 60-month loan at 7%. The calculator works backward from that $400 payment to find the maximum loan amount, then the maximum vehicle price that fits within it.
Key Concepts
Trade-in tax credit: most states knock your trade-in value off the taxable amount, which can meaningfully cut the sales tax on a trade-in deal.
Rolling in fees vs. paying upfront: rolling fees into the loan spreads the cost out with interest attached, while paying upfront avoids that extra cost entirely.
Affordability runs in reverse: instead of starting from a car price, this mode starts from what you can pay each month and solves backward for the loan amount and vehicle price.
The term length trade-off: a longer term means a lower monthly payment, but more total interest paid and a longer stretch of owing more than the car is worth.
Common Mistakes
Not checking your state's trade-in tax rule: whether your state gives a trade-in tax credit can change your total sales tax and loan amount more than people expect.
Rolling every fee into the loan without thinking it through: those fees now accrue interest for the full term, turning a one-time cost into an ongoing one.
Comparing a calculator estimate straight against a dealership quote: "out the door" prices often bundle in extras like extended warranties or gap insurance that a plain calculation won't capture.
Picking the longest term just for the lowest monthly number: without weighing the extra interest or the depreciation risk that comes with it.
Frequently Asked Questions
In most states, yes. You only pay sales tax on the difference between the new vehicle's price and your trade-in value, known as a trade-in tax credit. A few states, California among them, tax the full purchase price no matter what you trade in, so check your state's rule before assuming the credit applies to you.
Rolling fees into the loan means less cash out of pocket at signing, but you'll pay interest on those fees for as long as the loan runs. Paying them upfront saves you a bit of interest and keeps your loan amount lower.
Rather than starting with a vehicle price and calculating what it costs monthly, this mode starts with a payment you're comfortable making and works backward to find the loan amount and vehicle price it can support, once your down payment, trade-in, sales tax, and fees are factored in.
Dealership quotes often bundle in extras like extended warranties, gap insurance, or dealer fees that a plain loan calculation won't capture. They might also be using a different interest rate than what you're pre-approved for elsewhere, or applying sales tax in a way that doesn't quite match your state's actual rule.
It lowers your monthly payment, but you end up paying more interest overall since you're borrowing the same amount for longer. There's also a practical risk: cars lose value faster than a long loan pays down principal, so you can end up owing more than the car is worth for a longer stretch.