How to Calculate Your Auto Loan
Enter the vehicle price in the Vehicle Price field.
Enter the annual interest rate offered by your lender.
Select the loan term from the dropdown (24 to 84 months).
Optionally enter a down payment, trade-in value, sales tax percentage, and any additional fees.
Click Calculate to see your monthly payment, total interest, and full cost breakdown.
How the Auto Loan Calculator Works
The calculator uses the standard loan amortization formula to compute your fixed monthly payment. It first determines the loan principal — vehicle price, minus your down payment and trade-in value, plus sales tax (if provided) and any other fees. It then applies the monthly interest rate (annual rate divided by 12) over the selected number of months to produce a monthly payment that fully pays off the loan by the final installment. From there it derives total interest (total paid minus principal) and total cost of the vehicle (price plus tax plus fees plus total interest).
Step-by-Step Example
- Vehicle price: 28,000. Down payment: 4,000. Trade-in: 3,000. Sales tax: 8%. Fees: 600.
- Sales tax amount: 28,000 × 8% = 2,240.
- Loan principal: 28,000 − 4,000 − 3,000 + 2,240 + 600 = 23,840.
- Annual rate 6.5%, term 60 months → monthly rate r = 6.5 / 12 / 100 = 0.005417.
- Monthly payment: 23,840 × [0.005417 × (1.005417)^60] / [(1.005417)^60 − 1] ≈ 465.61.
- Total paid on loan: 465.61 × 60 = 27,936.60. Total interest: 27,936.60 − 23,840 = 4,096.60.
- Total cost of vehicle: 28,000 + 2,240 + 600 + 4,096.60 = 34,936.60.
When to Use This Calculator
- Comparing loan offers with different rates, terms, or down-payment amounts.
- Estimating your budget before visiting a dealership.
- Understanding how a trade-in or larger down payment reduces your monthly payment and total interest.
- Seeing the full cost of financing vs. paying cash.
- Preparing documentation for a loan application or personal records.
- Evaluating the impact of a shorter vs. longer loan term on total interest paid.
Tool Advantages And Limitations
Sales Tax And Rounding Considerations
This calculator applies sales tax to the full vehicle price before subtracting the down payment or trade-in value, which is a common convention but may differ by local jurisdiction. All monetary results are rounded to two decimal places, which may cause minor discrepancies in the final cent compared to a lender's exact amortization schedule.
Key Features
Exact Amortization Payment Calculation
Computes your precise monthly obligation using the standard amortization formula, eliminating guesswork for budget planning.
Complete Ownership Cost Breakdown
Reveals the true financial impact by displaying total interest, taxes, and fees alongside the principal to prevent budget shortfalls.
Interactive Visual Cost Distribution
Uses a pie chart to instantly highlight how much of your total spend goes toward interest versus the vehicle price.
One-Click PDF Loan Summary Export
Generates a professional document with all calculation details for immediate sharing with lenders or personal record-keeping.
Privacy & Security
All calculations run entirely in your browser using JavaScript. No values are sent to any server, stored, or logged. It is safe to use with personal financial details.
Frequently Asked Questions
What formula is used to calculate the monthly payment?
The standard loan amortization formula: M = P × [r(1+r)^n] / [(1+r)^n - 1], where P is the principal (loan amount), r is the monthly interest rate (annual rate / 12 / 100), and n is the number of months. If the interest rate is 0%, the payment is simply P divided by n.
How is the loan principal calculated?
Principal = Vehicle Price − Down Payment − Trade-In Value + Sales Tax + Fees. The sales tax is calculated on the full vehicle price before subtracting down payment or trade-in.
Why is sales tax applied to the full vehicle price?
In many regions, sales tax is assessed on the sticker price of the vehicle before any credits. The calculator follows this common convention, but the exact rule varies by location. Check with your dealer or tax authority for your region's rules.
What is the total cost of the vehicle?
Total Cost = Vehicle Price + Sales Tax + Fees + Total Interest Paid. This represents the full amount you pay for the vehicle over the life of the loan, compared to paying cash (Vehicle Price + Sales Tax + Fees).
Can I use this for any currency?
Yes. No currency symbol is assumed. Enter values in any currency and interpret the results accordingly.