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Car Loan Calculator

Calculators · Added 15 August 2026

Work out a car or auto loan payment including the things that actually determine it: sales tax, your trade-in, anything still owed on that trade-in, and dealer fees. The amount financed is rarely the sticker price, and this shows how it is built up line by line.

The negotiated price, before tax and fees

Financed with the loan

Anything above the trade-in value is rolled into the new loan

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Term unit

How to use the car loan calculator

  1. 1Enter the negotiated vehicle price, before tax and fees.
  2. 2Add your cash down payment and any dealer or registration fees.
  3. 3Enter your trade-in value and anything still owed on it.
  4. 4Set the sales tax rate, and tick the box if your state taxes the price after the trade-in is deducted.
  5. 5Enter the APR and term, then read the payment and the full breakdown.

Examples

A typical purchase

Input
$35,000 car · $5,000 down · $8,000 trade-in · 7% tax · $500 fees · 60 months at 7.5%
Result
$24,390 financed · $488.71 a month

The trade-in tax credit saved $560 in this example.

Without the trade-in tax credit

Input
The same purchase in a state that taxes the full price
Result
$24,950 financed — $560 more

Most US states allow the credit; a few do not, and on an expensive car the difference is significant.

Negative equity rolled in

Input
$30,000 car · $5,000 trade-in worth · $9,000 still owed
Result
$34,000 financed — $4,000 more than the car costs

You start the new loan owing more than the vehicle is worth.

About the car loan calculator

The amount financed is the number that matters

Car buyers negotiate the price and then finance something quite different. Sales tax is added, dealer and registration fees are added, the down payment and trade-in come off, and any negative equity from the old car goes back on. The result can be several thousand either side of the price you agreed.

This is why the monthly payment is a poor thing to negotiate on. A payment can be brought down by extending the term, by rolling costs forward, or by adjusting the trade-in allowance against the price — all of which can leave you paying more in total while the monthly figure improves. The amount financed, the APR and the term together determine the real cost, and any two of them can be traded against the third.

The practical defence is to agree the vehicle price first, in isolation, then discuss the trade-in, then discuss financing. Bundling all three lets movement in one hide movement in another, which is precisely why the conversation is often structured that way.

Depreciation, and why it drives everything else

A new car loses value fastest in its first years — commonly a fifth or more in the first twelve months. A loan, meanwhile, pays down slowly at first because early payments are mostly interest. Those two curves diverging is what puts a borrower underwater, and the longer the term, the wider and longer-lasting the gap.

That is the real argument against very long car loans, more than the extra interest. A 60-month loan on a car with a reasonable down payment typically stays roughly level with the vehicle's value. An 84-month loan with nothing down can leave you owing more than the car is worth for most of the loan's life, so any accident, sale or change of circumstances during that period costs money out of pocket.

It is also why gap insurance exists and is genuinely useful in this situation: if the car is written off while you are underwater, a standard insurance payout covers the vehicle's value, not the loan balance, and gap cover pays the difference. Needing it is a symptom of the loan structure rather than a solution to it, but if the structure is already in place the cover is not unreasonable.

Frequently asked questions

Is a car loan calculator the same as an auto loan calculator?
Yes — the two names describe the same thing, with 'auto loan' more common in the United States and 'car loan' elsewhere. This calculator covers both, and the maths is identical: an amortising instalment loan with sales tax and trade-in handling on top.
How does a trade-in affect sales tax?
In most US states, sales tax is charged on the price after the trade-in value is deducted, so trading in a $8,000 car at a 7% rate saves $560 in tax on top of the $8,000 off the price. A handful of states tax the full purchase price regardless. The checkbox on this calculator lets you model either, because on an expensive vehicle the difference runs into four figures. Check your own state's treatment before relying on the figure.
What is negative equity and why does it matter?
It is owing more on your current car than it is worth — being 'underwater'. When you trade it in, that shortfall does not disappear; it gets added to the new loan. Financing $4,000 of old debt on top of a new car means starting immediately underwater on the new loan too, paying interest on a vehicle you no longer own. It is common on long loans, because cars depreciate faster than a 72- or 84-month loan pays down.
Is a longer loan term a good idea?
It lowers the monthly payment and raises almost everything else. A longer term means more total interest, slower equity building, and a longer period underwater — a 72- or 84-month loan on a car that depreciates normally can leave you owing more than it is worth for years. If the payment only works at 84 months, that is usually information about the price rather than about the term.
Does the APR include dealer add-ons?
No. This calculates interest on the amount financed at the APR you enter. Extended warranties, gap insurance, paint protection and similar products are frequently rolled into the financed amount at the desk, which increases both the loan and the interest paid on it. If those are being added, include them in the fees field to see their real cost over the term — it is usually considerably more than the sticker price of the product.

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