Auto Loan Calculator

Free online auto loan calculator. Enter car price, down payment, APR and term to see monthly payment, total interest and total cost, plus a year-by-year principal vs. interest chart.

Know your monthly payment before you sign. Enter the car price, down payment, APR and loan term to see your monthly payment, principal financed, total interest and total cost, with a chart of yearly principal vs. interest.

Monthly Payment
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Loan Principal
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Total Interest
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Total of Payments
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Auto Loan Essentials

How Auto Loans Work

Auto loans are typically amortised: the monthly payment is fixed and every dollar splits into principal and interest. Early payments are interest-heavy; later payments are principal-heavy. The monthly payment formula:

Payment = P × r × (1+r)^n / ((1+r)^n − 1)
P = price − down payment
r = APR / 12
n = years × 12

Worked Example

$30,000 car, $6,000 down, $24,000 financed at 6% APR for 5 years (60 months):

  • Monthly payment ≈ $464
  • Total paid ≈ $27,840
  • Total interest ≈ $3,840

What Moves the Payment

  • Down payment: more down = lower payment and less interest.
  • Term: 3 vs. 5 years dramatically changes both monthly cost and total interest.
  • APR: bank, captive lender and dealer rates can differ by 3–6 percentage points.
  • Fees: origination fees, doc fees and mandatory add-ons push the effective APR up.

Loan vs. Cash

Aspect Loan Cash
Cash flow Preserves emergency fund Depletes savings
Total cost Price + interest + fees Price only
Flexibility Fixed monthly outlay Freedom
Hidden cost Add-ons, insurance None

Common Pitfalls

  1. "0% APR" traps: often forfeit cash rebates, force high-margin insurance or add fees.
  2. Low-payment illusion: stretching the term drops the payment but explodes total interest.
  3. Add-on stacking: gap insurance, extended warranties, VIN etching add hundreds or thousands.
  4. Prepayment penalties: read the contract before making extra payments.

About This Tool

We use standard amortisation with monthly compounding, and plot yearly principal vs. interest so you can see the crossover point where you finally start paying down the balance faster.

Open-Source License: Monthly payments use the AM helper from finance.js by Essam Al Joubori (MIT), and charts use Chart.js by Chart.js contributors (MIT). Both are bundled locally.

Frequently Asked Questions

How large should the down payment be?
20% on new vehicles is the common benchmark in the US; higher for luxury imports. A larger down payment lowers monthly cost, total interest and the chance of being underwater on the loan.
Is 0% APR really free money?
Almost never. Zero-APR promos typically require you to forfeit cash rebates and often pair with mandatory add-ons. Compare the total out-the-door price, not just the rate.
Why does most of my early payment go to interest?
Because interest is charged on the remaining balance, which is highest at the start. It is not a scam—just the math of amortisation.
Longer term or shorter term?
Shorter terms minimise interest and get you above water faster. Longer terms cut monthly outlay but increase risk. 3–5 years is a common sweet spot.
Is prepayment a good idea?
Yes if your APR exceeds what you can earn safely elsewhere (say 5%). Check for prepayment penalties first.
What are the bars in the chart?
One bar per year. Amber is principal repaid that year; red is interest paid that year. Watch the red shrink and amber grow over time—that is deleveraging in action.
What happens if I miss a payment?
Expect late fees, higher effective rate and hits to your credit score. Keep 1–2 months' payment in reserve to protect against interruptions.