Auto · 2026 rules
Auto Loan Calculator
Monthly payment, total interest and how much of the sticker price turns into interest, including sales tax, trade-in and negative equity.
The short answer
The vehicle
Your state and local combined rate. Some states tax the price after trade-in.
What you put down
Anything above the trade-in value rolls into the new loan.
The loan
Monthly payment
$629.43
72 payments on $36,660.00 borrowed at 7.25%.
What you actually pay
The sticker price is not the price. Tax and interest are the rest of it.
Vehicle: $38,000 (77.0%), Sales tax: $2,660 (5.4%), Interest: $8,659 (17.6%)
- Vehicle$38,000
- Sales tax$2,660
- Interest$8,659
Vehicle price
Sales tax
7.00% of $38,000 after trade-in
Cash down
Amount financed
Total interest
23.6% of what you borrowed
Total out of pocket
What you still owe
Compare this against what the car will be worth. That gap is how long you stay underwater.
Hover the chart to read any year.
Show the mathEvery payment, split into interest and principal
| Year | Interest | Principal | Balance |
|---|---|---|---|
| 1 | $2,491.85 | $5,061.25 | $31,598.74 |
| 2 | $2,112.47 | $5,440.65 | $26,158.10 |
| 3 | $1,704.67 | $5,848.46 | $20,309.64 |
| 4 | $1,266.26 | $6,286.84 | $14,022.79 |
| 5 | $795.02 | $6,758.11 | $7,264.68 |
| 6 | $288.42 | $7,264.67 | $0.00 |
What this does not include
Questions
What people ask
Is a 72- or 84-month loan a bad idea?
It lowers the payment and raises the total cost, and it keeps you underwater for longer, owing more than the car is worth. Compare the total interest at 48, 60 and 72 months; the payment difference is small next to the interest difference.
What is negative equity and why does it matter?
It is the gap when you owe more on your trade-in than it is worth. Dealers will roll it into the new loan, which means you start the new car already underwater and pay interest on the old car's debt for years.
Is sales tax charged before or after the trade-in?
Most states tax the price after deducting the trade-in, which is what this calculator assumes. A few, including California and Michigan in part, tax the full price. Check your state if the trade-in is large.
Keep going
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United States tax figures for 2026, last reviewed August 1, 2026. Every rate used here is listed with its source on the official rates page.