The calculator above adds up what a new car really costs to drive home: the selling price plus add-ons, doc fee, sales tax, title and registration, minus rebates and your trade-in. Enter the numbers from a dealer's written quote and the result should match their out the door total. If it does not, something in the quote needs explaining.
What each input means
Selling price
This is the price you and the dealer agree for the car itself, before fees and taxes. It is not the MSRP on the window sticker, and it is not a monthly payment. Ask the dealer whether the destination charge is already included in the selling price; on most quotes it is, and you should not add it twice. If you are not sure what a fair selling price looks like, our guide to invoice vs MSRP explains the reference points.
Add-ons
Enter the total of any dealer-installed products or packages on the quote: paint protection, nitrogen, VIN etching, tint, wheel locks, accessory packages, and any service contract or GAP you plan to buy. Enter zero if you have asked for none. Most of these are optional. Our dealer add-ons guide sorts which ones you can refuse and how to get them removed in writing.
Rebates
Enter manufacturer cash offered to buyers, such as a customer rebate or loyalty offer. Do not enter dealer cash, which is paid to the dealer and should already be reflected in a lower selling price. Some rebates require financing through the brand's lender, and some states charge sales tax on the price before the rebate is subtracted, so the order in which the dealer applies it matters. Ask the dealer to show the rebate as its own line.
Doc fee
The documentation fee is charged by the dealer for processing paperwork. It is set by the dealer, and some states cap it. CarEdge reports a national average of $477, with Florida dealers averaging $973, in its dealer fee report. The same report lists a reported cap of $398 in Ohio. State rules change, so check your state's current rule. See doc fees by state for the full reported table.
Sales tax rate
Enter the combined rate for where you will register the car, which usually means your state rate plus any county or city rate. Your state revenue department or DMV publishes the rate. If you are buying from a dealer in another state, tax generally still follows your home address; our guide to buying a car out of state covers how that works. The calculator applies tax to the selling price plus add-ons and doc fee. States differ on whether doc fees, rebates and trade-ins affect the taxable amount, so treat the tax line as an estimate and confirm with your state.
Title and registration
These are government fees for issuing the title, plates and registration. They vary by state and sometimes by vehicle weight, value or age. Use your DMV's fee schedule, or the figure on the dealer's quote if it is itemized. If you are transferring plates from your old car, the cost may be lower.
Trade-in
Enter your trade-in value and your loan payoff separately if the calculator asks for both. The difference is your equity. If you owe more than the car is worth, that negative equity gets added to what you pay, not subtracted. This is common: Edmunds found 29% of trade-ins toward new vehicles carried negative equity in late 2025, with an average of $7,214 owed, per a presentation to the Chicago Fed. Many states reduce the taxable price by the trade-in value, but not all do.
A worked example with hypothetical numbers
Say you agree on a $40,000 selling price for a car with no add-ons, a $1,000 customer rebate, a $500 doc fee, a 6% sales tax rate and $300 in title and registration. You have a trade-in worth $10,000 that is paid off. This example assumes your state taxes the price after the trade-in but before the rebate, which is one common approach.
| Line | Amount |
|---|---|
| Selling price | $40,000 |
| Add-ons | $0 |
| Doc fee | $500 |
| Taxable amount ($40,000 + $500 minus $10,000 trade) | $30,500 |
| Sales tax at 6% | $1,830 |
| Title and registration | $300 |
| Rebate | minus $1,000 |
| Trade-in equity | minus $10,000 |
| Amount due | $31,630 |
With the trade-in, the out the door price is $41,630 and the trade covers $10,000 of it. Without the trade-in, the out the door price would be $42,230, because tax would be calculated on $40,500 instead of $30,500. Small rule differences move the total by hundreds of dollars, which is why the calculator result is an estimate and the dealer's written buyer's order is the final word.
How to read your result
The result has three numbers worth separating.
- Out the door price. Everything you pay for the car, fees and taxes included, before your trade-in and down payment. This is the number to compare between dealers.
- Amount due. What you owe after trade-in equity. If you are paying cash, this is your check.
- Amount financed. The amount due minus any down payment. This is what goes on the loan.
Compare dealers on the out the door price, not the amount financed or the monthly payment. A lower payment can hide a longer loan, a higher rate or add-ons rolled into the balance. Consumer Reports advises against negotiating on the monthly payment for this reason, in its negotiation guide.
If your result differs from the dealer's total by more than a few dollars, find the line that does not match. The usual suspects are an add-on you did not expect, a different tax rate, or a rebate that was not applied.
Common mistakes
- Entering MSRP as the selling price. The average buyer paid about 3.4% below the average MSRP in August 2026, according to Kelley Blue Book data reported by Digital Dealer. Use the negotiated number.
- Counting the destination charge twice. It is usually already in the selling price.
- Subtracting dealer cash. Only enter rebates paid to you.
- Using only the state tax rate. Local taxes can add to it.
- Treating trade-in value as equity. Subtract your payoff first.
- Leaving out delivery or travel. For a distant dealer, add the cost of getting the car home before you compare.
- Ignoring the financing cost. Two deals with the same out the door price can cost very different amounts over a loan. Experian put the average new-car APR at 6.35% in the second quarter of 2026, per Auto Remarketing. A credit union or bank pre-approval gives you a rate to measure the dealer against.
Getting numbers worth calculating
A calculator is only as good as the quote you feed it. Ask each dealer for a written, itemized out the door price, using the wording in our guide to negotiating the out the door price by email, and run each one through the calculator. If you would rather not email a dozen dealers yourself, SnagMyCar does that part: we collect written, itemized quotes from every matching dealer in your radius, ask them to beat the best one, and show you the totals side by side. See how it works and pricing, or start your search.
Questions
What is included in an out the door price?
The out the door price is the full amount to buy the car before your trade-in and down payment: the selling price, any dealer add-ons, the doc fee, sales tax, and title and registration fees, minus any manufacturer rebates. It is the number to compare between dealers because it captures fees that a selling price leaves out.
Why does my calculator result not match the dealer's quote?
The most common causes are an add-on you did not expect, a different sales tax rate, a rebate that was not applied, or a different rule for taxing the doc fee, rebate or trade-in. Compare the dealer's itemized quote line by line with what you entered. If a line is missing from the quote, ask the dealer to itemize it.
Is sales tax charged before or after a trade-in?
It depends on your state. Many states tax only the price after the trade-in value is subtracted, which lowers your tax bill, but some tax the full selling price. Rebates also vary: some states tax the price before the rebate comes off. Check your state revenue department or DMV, and treat the calculator's tax line as an estimate.
Should I include the destination charge in the selling price?
Usually it is already included. The destination charge is printed on the window sticker, and most dealer quotes fold it into the selling price. Ask the dealer to confirm, and do not add it again in the add-ons field. Doubling it is one of the most common reasons a calculated total comes out too high.
How do I handle negative equity in the calculator?
Enter your trade-in value and your loan payoff. If the payoff is higher than the value, the difference is negative equity, and it increases what you owe rather than reducing it. It usually gets added to the new loan. Knowing the exact figure before you shop helps you decide whether to trade in now or pay down the old loan first.