The out-the-door price formula
Financing interest is separate because it depends on the amount borrowed, APR and loan term rather than the vehicle transaction alone.
The taxable base may differ from the negotiated price. Some locations tax certain add-ons; some allow the trade-in value to reduce the taxable amount; others do not. This calculator exposes that assumption instead of silently choosing one rule for every buyer.
How to compare two dealer quotes without payment tricks
Ask each dealer to email a buyer’s order or worksheet for the exact stock number. Compare the selling price, each discount, each add-on, the tax rate, documentation fee and government charges line by line. A quote with a lower monthly payment may simply have a longer term, larger deposit or omitted item.
Only finance the price after you understand it
Once the out-the-door total is agreed, subtract cash down and usable trade equity to estimate the amount financed. Then compare APR, term, monthly payment and total interest. If you owe more than the trade-in is worth, do not subtract its full value: calculate the net equity first.
Use the negative equity trade-in calculator for an existing loan, then check the resulting payment with the affordability calculator.
Sources and checks
AutoPrisme uses the figures you enter. The links below explain the rule, market context or consumer protections used to frame this calculator. Always verify the numbers in your own quote or contract.
- Federal Trade Commission — Car dealer ads and promotionsUS consumer guidance recommending a written out-the-door price containing all charges and fees.
- Federal Trade Commission — Financing or leasing a carGuidance on separating total vehicle price, add-ons and finance terms.
- CarEdge — Out-the-door price calculatorA current example of the strong US buyer intent around taxes, title, registration and documentation fees.
Frequently asked questions
What is an out-the-door car price?
It is the complete vehicle price before financing, including the agreed selling price, applicable taxes, dealer charges, title and registration fees and any add-ons you accept.
Is a down payment part of the out-the-door price?
No. A down payment changes how the total is funded; it does not reduce the underlying out-the-door price. Keep price negotiation separate from financing and cash due at signing.
Does a trade-in reduce sales tax?
It depends on the state, province or territory and the transaction. The calculator lets you turn the trade-in tax credit on or off, but you should verify the applicable rule with the local motor-vehicle or tax authority.
Which dealer add-ons should I include?
Include every product on the buyer's order: protection packages, service contracts, accessories, GAP products, etching and any market adjustment. Do not assume an add-on is mandatory without checking.