Auto Loan Calculator
Estimate your monthly car loan payment, total interest, state sales tax, trade-in credit allowance, and dealer fees. Supports 24 to 84-month loan terms with full yearly and monthly amortization schedules.
Auto Loan Details
Amortization Schedule Breakdown
How Auto Loan Payments & Financing Work
Financing a vehicle involves calculating fixed monthly installments that combine principal repayment with compounding interest across the agreed loan duration (typically 24 to 84 months). Unlike personal or real estate loans, auto financing incorporates unique upfront variables—including trade-in allowances, dealer documentation fees, title and registration costs, and state sales taxes.
Worked Step-by-Step Example
Suppose you buy a vehicle priced at $35,000 with a $5,000 trade-in, $3,500 down payment (10%), 6.5% sales tax, and 5.5% interest rate over 60 months:
- Taxable Purchase Base:
$35,000 − $5,000 trade-in = $30,000 - Sales Tax (6.5%):
$30,000 × 0.065 = $1,950 - Net Financed Amount:
$35,000 − $3,500 down − $5,000 trade + $1,950 tax + $800 fees = $29,250 - Monthly Payment (60 mo @ 5.5%): $558.82 / month
- Total Interest Paid:
($558.82 × 60) − $29,250 = $4,279.20
The 20/4/10 Rule for Car Financing
Frequently Asked Questions
Monthly car payments are calculated using fixed-rate amortization: P = L[c(1 + c)^n] / [(1 + c)^n - 1], where L is the net financed loan amount (Vehicle Price - Down Payment - Trade-in + Taxes & Fees), c is the monthly interest rate (Annual Rate / 12), and n is the total number of months (e.g., 60).