Auto Loan Calculator
Calculate car payments including trade-in, sales tax, fees and rebates.
About Auto Loan Calculator
The amount financed equals the vehicle price plus sales tax, minus your down payment and any trade-in value. That balance is then amortized across your chosen term at the given APR.
Formulas
Amount financed
Financed = Price + Tax − Down Payment − Trade-in
- F
- Amount financed (loan principal)
- P_price
- Vehicle purchase price
- T_tax
- Sales tax = Price × Tax Rate
- D
- Down payment
- V
- Trade-in value
Monthly payment
M = F · r / (1 − (1+r)^−n)
- M
- Monthly payment
- r
- Monthly interest rate = APR ÷ 12
- n
- Loan term in months
Worked example
With the default values below, Auto Loan Calculator returns Monthly Payment of $641.02. Change any input above and every figure here is recalculated in your browser.
Inputs used
- Vehicle Priceaccepts 1,000–300,000 $
- 35,000 $
- Down Paymentaccepts 0–100,000 $
- 5,000 $
- Trade-in Valueaccepts 0–100,000 $
- 0 $
- Sales Taxaccepts 0–15 %
- 7 %
- Interest Rate (APR)accepts 0–30 %
- 6.9 %
- Loan Termaccepts 12–96 months
- 60 months
Results
- Monthly Payment
- $641.02
- Amount Financed
- $32,450.00
- Sales Tax
- $2,450.00
- Total Interest
- $6,011.14
Step by step
- 1Vehicle price= $35,000.00
- 2Sales tax on vehicle price= $2,450.00
- 3Amount financed: Price + Tax − Down Payment − Trade-in= $32,450.00
- 4Monthly interest rate: APR ÷ 12= 0.5750%
- 5Monthly payment: M = P · r / (1 − (1+r)⁻ⁿ)= $641.02
- 6Total interest: Total Paid − Amount Financed= $6,011.14
Assumptions and limits
- The result is derived only from the 6 inputs listed above. Anything not among them is not part of the calculation.
- In particular, this calculator does not take inflation, fees or charges or compounding frequency into account.
- Figures are rounded for display to 2 decimal places, so totals built from several rounded parts can differ slightly from the unrounded arithmetic.
- Estimates only and not financial advice. Confirm tax and financing terms with your dealer and lender.
- This is an estimate for general information and not professional financial, tax or legal advice. See the full disclaimer for the limits that apply to this kind of calculator.
How these calculators are built and tested is described on the Methodology page. If a figure looks wrong, please report it.
Auto Loan Calculator — full guide
What this calculator answers
You are at a dealership with a price on the windscreen, a down payment in mind, and a finance desk that keeps offering to stretch the term. The useful question is not "can I afford the payment" but "what am I financing, and what does the interest cost". This tool takes the vehicle price, down payment, trade-in value, sales tax rate, APR and term in months, and returns the monthly payment, the amount financed, the sales tax and the total interest.
Step one — the amount financed
Financed = Price + Tax − Down Payment − Trade-in
Sales tax here is applied to the full vehicle price. Several U.S. states let a trade-in reduce the taxable amount, so if yours does, your real tax bill will be lower than the figure shown. Treating the full price as taxable keeps the estimate on the cautious side.
Step two — spreading that balance over the term
M = F · r / (1 − (1 + r)^−n)
- F is the amount financed from step one
- r is the monthly rate: the APR divided by 12
- n is the number of monthly payments
Worked example, using the defaults
A $35,000 vehicle, $5,000 down, no trade-in, 7% sales tax, 6.9% APR, 60 months.
| Step | Value |
|---|---|
| Sales tax, 7% of $35,000 | $2,450 |
| Amount financed | $32,450 |
| Monthly rate, 6.9% ÷ 12 | 0.00575 |
| Monthly payment | $641.02 |
| 60 payments total | $38,461.14 |
| Total interest | $6,011.14 |
Interest is $6,011 of the $38,461 you hand over — about 15.6% of the total. In the very first payment, $186.59 is interest and $454.43 reduces the balance.
Reading the result against the term
Stretching the same $32,450 to 72 months drops the payment to $551.68 but raises total interest to $7,271.20. Pulling it in to 48 months lifts the payment to $775.55 and cuts interest to $4,776.45. The payment moves by a little; the interest moves by a lot.
What the estimate leaves out
- Title, registration, documentation fees, extended warranties and gap insurance are not inputs. Anything rolled into the contract adds roughly $19.75 a month per $1,000 at these defaults.
- The payment is principal and interest only. Insurance, fuel and maintenance sit outside it.
- Negative equity on a trade-in cannot be entered as a negative value; add it to the price instead.
- A single fixed APR is assumed for the whole term.
This is an estimate, not financial advice — confirm the tax and contract rate with your dealer.
Related: Loan Calculator, Sales Tax Calculator, Amortization Calculator.
Estimates only and not financial advice. Confirm tax and financing terms with your dealer and lender.
Frequently Asked Questions
Does trade-in reduce sales tax?
In many U.S. states a trade-in reduces the taxable amount, but rules vary. This calculator applies sales tax to the full vehicle price to stay conservative.
What term should I choose?
Shorter terms mean higher monthly payments but far less total interest. Longer terms lower the payment but cost more overall.
Why is the dealer's quoted payment higher than the figure here?
Dealers usually fold in documentation fees, title and registration, and often an extended warranty or gap policy — none of which are inputs on this page. At the default 6.9% APR over 60 months, every extra $1,000 added to the contract raises the payment by about $19.75. Ask for the amount financed, then re-enter it as the vehicle price with zero tax to check their maths.
Should I enter my trade-in's appraised value or what I still owe on it?
Enter the appraised value the dealer is crediting you, not your payoff. Adding a $4,000 trade-in to the default example drops the financed balance from $32,450 to $28,450 and the payment from $641.02 to $562.00. If you owe more than the car is worth, leave the trade-in at 0 and add the negative equity to the vehicle price instead.
What does putting nothing down do to the default example?
Removing the $5,000 down payment raises the financed amount to $37,450 and the monthly payment to $739.79, with total interest of $6,937.36 instead of $6,011.14. The down payment is the one input that cuts both the payment and the interest at once, which is why it does more for the total cost than shaving the rate by a quarter point.
Which rate belongs in the APR field — the one advertised or the one on the contract?
Use the rate on the contract you are actually signing. Advertised rates assume top-tier credit, and dealer-arranged financing can carry a markup over the rate the bank approved. The APR field is treated as a plain nominal annual rate and divided by 12, so entering a promotional rate you do not qualify for will understate every result on the page.