Short answer: the sticker price is not what a car costs. This calculator adds the sales tax, subtracts your down payment and trade-in, and shows the payment, the total interest, and the car’s true all-in cost. Example: a $35,000 car with $5,000 down and a $2,000 trade-in at 8.5% for 60 months means financing $30,310 and paying $621.86 a month — $44,311 all-in.
| Amount financed (price + tax − down − trade-in) | — |
| Sales tax included | — |
| Total interest over the loan | — |
| True total cost of the car (everything you pay) | — |
See the full breakdown
Educational estimate only — not financial advice or a loan offer. Sales tax is calculated on the price minus trade-in value, which is how most (not all) states treat trade-ins; dealer fees, registration, and add-ons are not included — add them to the price for a closer figure.
How this calculator works
Amount financed = price + sales tax − down payment − trade-in. Tax is charged on the price minus trade-in value (the rule in most states). The payment then comes from the standard amortization formula, and the true total cost adds back everything: your down payment, your trade-in, and every monthly payment.
Worked example
- Price $35,000, tax 7% on ($35,000 − $2,000) = $2,310, down $5,000, trade-in $2,000 → financed $30,310.
- At 8.5% for 60 months → $621.86/month, total interest $7,001, true total cost $44,311.
- No-trade-in case: $20,000 car, 6% tax, $2,000 down, 6% APR, 48 months → financed $19,200, payment $450.91.
FAQs
Why does the term matter so much? Stretching 60 months to 84 lowers the payment but stacks up interest and keeps you owing more than the car is worth for longer. Compare two terms before you sign. Should my trade-in reduce the tax? In most states, yes — the calculator assumes so and says so. A few states tax the full price; raise the tax amount by editing the price if yours does. What’s a sane payment rule? A common guardrail: keep total car costs (payment + insurance + fuel) under roughly 15% of take-home pay, and put at least 10–20% down on a new car to avoid going underwater.
Sources: CFPB: how to compare auto loan offers, FRED RIFLPBCIANM60NM (60-month new auto loan rate) Figures last verified Report a wrong number