Car Loan Calculator with Trade-In
This free car loan calculator with trade in estimates your monthly payment when you're trading in a car you still owe money on. Enter the vehicle price, your trade-in value, and what you owe on your current loan, and it works out your trade-in equity, net price, taxes, and the true cost of your new loan — instantly, on any device.
Enter your numbers
Your results
Loan summary
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Principal vs interest
Estimate only — not lending advice. Sales tax is applied to the net price (vehicle price minus trade-in equity); some states tax the full sticker price instead — see How it works. Actual loan offers vary by lender, credit history, fees, and your state's tax rules.
How to use this calculator
Start with the vehicle price of the car you want, then describe your current situation: the trade-in value the dealer is offering and the payoff owed on your existing loan. The difference between those two is your trade-in equity — $3,000 of equity in the default example ($8,000 value minus $5,000 owed) — which works like an extra down payment.
Add any cash down payment, your state's sales tax rate, the APR you've been quoted, and a loan term — 36, 48, 60, or 72 months are the most common, or type any term from 6 to 96 months. Results update instantly as you change any input.
The results show your amount financed (the loan size after equity, tax, and down payment), your estimated monthly payment, and the total interest over the life of the loan. The donut chart shows how much of your total payments goes to principal versus interest. Try entering your real trade-in numbers from two or three dealers to see how a better trade offer changes the payment.
How it works
First the calculator finds your trade-in equity: trade-in value − payoff owed. In the default example, that's $8,000 − $5,000 = $3,000. If you owe more than the car is worth, the equity is negative and the shortfall gets rolled into your new loan (you're "upside down").
Next it computes the net price: vehicle price − trade-in equity ($25,000 − $3,000 = $22,000). Sales tax is applied to this net price — $1,540 at a 7% rate in the example. This matches how most states tax trade-ins, but a few states tax the full sticker price, so check your state's rules.
The amount financed is net price + tax − down payment ($22,000 + $1,540 = $23,540 in the example). That balance is spread into equal monthly payments with the standard amortization formula: M = L × r × (1+r)n / ((1+r)n − 1), where L is the amount financed, r is the monthly rate (APR ÷ 1200), and n is the number of months. With a 0% APR, the payment is simply L ÷ n.
Assumptions: the APR stays fixed for the whole term; payments are equal and made monthly; sales tax applies to the net price (not all states do this); dealer fees, registration, title, and insurance are not included. All figures are estimates for planning — not lending advice and not a loan offer.
Frequently asked questions
How does trading in a car I still owe money on affect my new loan?
Your old loan doesn't disappear — your dealer pays off the remaining balance when you trade the car in. First we compute your trade-in equity: the trade-in value minus what you still owe. With an $8,000 trade-in value and a $5,000 payoff, you have $3,000 of equity, which reduces the amount you need to finance. But if you owe more than the car is worth, that negative equity (being “upside down”) gets added to your new loan, increasing your monthly payment.
Do I pay sales tax on the full price or the net price after trade-in?
It depends on your state. Most states charge sales tax on the net price — the vehicle price minus your trade-in equity — so a trade-in lowers your tax bill. A few states charge tax on the full sticker price regardless of your trade-in. This calculator applies tax to the net price (vehicle price minus trade-in equity); if your state taxes the full price, set the tax rate to 0% here and add the tax to your budget separately, or check your state's rules before you buy.
What is trade-in equity and why does it matter?
Trade-in equity is the difference between what your current car is worth as a trade-in and what you still owe on it: trade-in value minus payoff owed. Positive equity works like an extra down payment — it shrinks the amount you finance, which lowers your monthly payment and the total interest you pay. Negative equity does the opposite: the shortfall gets rolled into your new loan, so you finance more than the new car's net price.
Is it better to pay off my trade-in before buying a new car?
If you have negative equity, paying down your current loan first can be smart — rolling a large shortfall into a new loan means financing more than the car is worth, which can leave you upside down again. But compare interest rates too: if your current loan has a low rate and your new loan would have a higher one, it may be cheaper to carry the old balance a bit longer and make a bigger down payment instead. This calculator shows you both scenarios, so compare the monthly payment and total interest.
Are these numbers a guaranteed loan offer?
No. Everything on this page is an estimate for planning only — not lending advice and not a loan offer. Actual terms will vary with your credit, the lender's fees, dealer fees, registration costs, and your state's tax rules.