onlinecalculator.me

Free online auto loan calculator

An auto loan is money you borrow to buy a car and pay back over time. This calculator shows your monthly payment and the total cost, including interest, taxes, and fees.

Loan amount
$—
Monthly payment
$—
Total interest
$—
About this calculator

How to use

  1. Enter the vehicle price, down payment, trade-in value, sales tax %, and any fees.
  2. Set the APR (from your lender) and loan term in months.
  3. Optionally add an extra monthly payment to see interest savings.
  4. The calculator shows the net loan amount, monthly payment, and total interest.
  5. Press “Show schedule” for the full month-by-month amortization table.

How the loan amount is calculated

Taxable base = price − down payment − trade-in
Sales tax    = taxable base × (tax% / 100)
Loan amount  = taxable base + sales tax + fees

Worked example

Vehicle: $35,000 | Down: $5,000 | Trade-in: $0 | Tax: 8% | Fees: $500 | Rate: 6.5% APR | Term: 60 months

  • Taxable base: $35,000 − $5,000 = $30,000
  • Sales tax: $30,000 × 0.08 = $2,400
  • Loan amount: $30,000 + $2,400 + $500 = $32,900
  • Monthly payment: ≈ $643/month
  • Total interest: ≈ $5,580

Notes

  • APR (Annual Percentage Rate) is the yearly cost of borrowing. Divide by 12 for the monthly rate.
  • Dealer markups on APR are common — compare the dealer’s rate against your bank or credit union before signing.
  • GAP insurance and extended warranties add to the effective cost of the loan and are not included here.

Frequently asked

How is the auto loan monthly payment calculated?
Same formula as a mortgage: M = L × r(1+r)^n / ((1+r)^n − 1), where L is the net loan amount after down payment and trade-in, r is the monthly rate (APR ÷ 12), and n is the term in months.
How does the trade-in value affect the loan?
The trade-in is subtracted from the vehicle price before sales tax is applied — the same way a down payment reduces the financed amount. This lowers the taxable base, which reduces both the loan amount and the sales tax you pay.
Is sales tax applied to the full vehicle price?
In most US states, sales tax is calculated on the vehicle price minus the down payment and trade-in (the "taxable amount"). The calculator follows this convention. Some states tax the full price — check your state's rules.
What fees are included?
The Fees field covers documentation fees, registration, and any dealer fees. They're added to the loan amount since most buyers roll them in rather than paying cash.
How does an extra monthly payment shorten the loan?
Extra payments go directly to principal, reducing the balance faster. The calculator simulates each month with the extra amount included and shows the revised payoff month and total interest saved.