Trade-In Car Loan Calculator
Calculate your car loan payment after applying your trade-in value. Handles positive and negative equity, sales tax credit, and dealer fees.
Your trade-in either reduces the new loan amount (if you have positive equity) or increases it (if you owe more than the trade is worth — negative equity). Both cases need careful handling because the dealer benefits when you don't see the math clearly.
Positive Equity Example
- Trade worth: $14,000
- Trade loan owed: $0 (you own it outright)
- Net trade equity: $14,000 reduces the new loan
Negative Equity Example
- Trade worth: $12,000
- Trade loan owed: $15,000
- Net trade equity: −$3,000, which rolls into the new loan
If the new car costs $30,000 and you have $3,000 of negative equity rolled in, you finance $33,000 worth of car on a $30,000 vehicle. You start the new loan immediately underwater.
Sales Tax Credit on Trade-In
Most US states allow your trade-in value to reduce the sales-tax base. On a $35,000 car with a $7,000 trade-in at 7% tax, you save $490. A few states (California, Virginia, Michigan, Maryland, Hawaii, DC) do not allow this credit; you pay sales tax on the full price regardless.
How to Verify Your Trade-In Value
- Get an instant offer from CarMax or Carvana. These are real bid prices, not estimates.
- Use Kelley Blue Book and Edmunds for the trade-in range. Compare against the CarMax offer.
- The dealer's first trade offer is almost always below CarMax. Bring the CarMax offer in writing and let them match or beat.
- Selling privately gets you 10-20% more than the dealer offer in most cases but loses the sales-tax credit. Do the after-tax math.
Use the Full Calculator
The Auto Loan Calculator handles every scenario described on this page. For the deeper math and worked examples, read the companion guide.