Quick answer
An auto loan is a fixed-rate loan on the amount you finance: the price minus your down payment and any trade-in value. Enter the price, down payment, trade-in, rate and number of months to see the monthly payment, the total interest and the total you will pay.
The payment formula is the same one used for any fixed-rate loan. Sales tax, registration and fees are not included, so add them to the price if you will finance them.
Related tools: Loan Calculator: Estimate your monthly loan payment, total interest and total cost. Loan Comparison Calculator: Compare the payment and total interest of two loans. Amortization Calculator: Full amortization schedule with optional extra monthly payments.
How to use the Auto Loan Calculator
- Enter vehicle price ($) (above 0).
- Enter down payment ($) (0 or more). It starts at 0.
- Optionally, enter trade-in value ($) (0 or more).
- Enter interest rate (APR) (%) (between 0 and 100).
- Enter term (months) (a whole number, between 1 and 120). It starts at 60.
- Press Calculate to see the result, and use Reset to start again.
| Input | What to enter | Allowed values |
|---|---|---|
| Vehicle price | A number, in $ | > 0 |
| Down payment | A number, in $ | ≥ 0, starts at 0 |
| Trade-in value (optional) | A number, in $ | ≥ 0 |
| Interest rate (APR) | A number, in % | ≥ 0, ≤ 100 |
| Term | A whole number, in months | ≥ 1, ≤ 120, starts at 60 |
Formula and method
Formula
loan = price − down payment − trade-in; M = L·i ÷ (1 − (1 + i)^−n)
IEEE-754 double precision; money shown to cents, rates to 4 decimals. Results are estimates, not financial advice.
Fixed-rate, fully amortizing loan with monthly compounding; excludes fees, insurance and taxes.
Worked examples
These examples are verified: each one is an automated test case that the live calculator must reproduce exactly.
Example 1
Inputs: Vehicle price = 30000; Down payment = 5000; Interest rate (APR) = 6; Term = 60.
| Result | Value |
|---|---|
| Monthly payment | $483.32 |
| Amount financed | $25,000.00 |
| Total interest | $3,999.20 |
| Total paid | $28,999.20 |
| Payments made | 60 |
Example 2
Inputs: Vehicle price = 20000; Down payment = 0; Trade-in value = 2000; Interest rate (APR) = 0; Term = 36.
| Result | Value |
|---|---|
| Monthly payment | $500.00 |
| Amount financed | $18,000.00 |
| Total interest | $0.00 |
| Total paid | $18,000.00 |
| Payments made | 36 |
The first line is the headline result (monthly payment). Below it the auto Loan Calculator lists amount financed, total interest, total paid and payments made, which describe the same case from other angles. IEEE-754 double precision; money shown to cents, rates to 4 decimals. Results are estimates, not financial advice.
Worked example
A $30,000 car with $5,000 down and no trade-in leaves $25,000 to finance. At 6% for 60 months the payment is $483.32, which over 60 payments is $28,999.20, so the interest is $3,999.20.
How the loan length changes the cost
The same $25,000 financed at 6% over different lengths: a longer loan lowers the payment but costs more interest.
Every figure in this table comes from running this calculator, so it matches what the form returns.
| Months | Monthly payment | Total interest |
|---|---|---|
| 36 | $760.55 | $2,379.74 |
| 48 | $587.13 | $3,182.03 |
| 60 | $483.32 | $3,999.20 |
| 72 | $414.32 | $4,831.20 |
What happens with invalid input
These messages are produced by the calculator itself, so you know what to fix.
- Down payment: entering "10000" shows "Down payment and trade-in must be less than the price." beside that field and no result.
Choosing between the Auto Loan Calculator and similar calculators
Each row shows what a related calculator on this site asks for and what it returns, so you can pick the one that matches your question.
| Calculator | You enter | It returns |
|---|---|---|
| [Loan Calculator](/finance/loan-calculator/) | loan amount, interest rate and term | Monthly payment |
| [Loan Comparison Calculator](/finance/loan-comparison-calculator/) | loan 1 amount, loan 1 rate and loan 1 term | Lower total interest |
| [Amortization Calculator](/finance/amortization-calculator/) | loan amount, interest rate and term | Monthly payment |
| [Interest Rate Calculator](/finance/interest-rate-calculator/) | loan amount, monthly payment and term | Interest rate (APR) |
| [HELOC Calculator](/finance/heloc-calculator/) | balance drawn, interest rate and draw period | Interest-only payment (draw period) |
Background: loans and mortgages
The interest rate is the cost of borrowing the principal; the APR also folds in certain fees, so a lower rate with high fees can have a worse APR. These calculators use the rate you enter and do not add fees, insurance or taxes, so add fees to the principal if you want to include them.
A fixed-rate loan is paid in equal instalments, early ones mostly interest. Extra payments go straight to principal, which shortens the loan and cuts interest; adjustable rates, escrow changes and prepayment penalties are not modelled.
Assumptions and limitations
- Down payment plus trade-in must be less than the price
- Excludes sales tax and fees
Results are estimates for planning, not financial advice. Lender terms, fees, taxes and rounding rules can change real figures, so confirm important numbers with your lender or a licensed adviser.
If a required value is empty, not a number, or outside its allowed range, the form marks that field with a message and shows no result instead of a misleading number. The automated checks deliberately try invalid entries for down payment to confirm this.
Frequently asked questions
What does the Auto Loan Calculator calculate?
Monthly car payment after down payment and trade-in. It returns Monthly payment, Amount financed, Total interest, Total paid and Payments made.
What formula does the Auto Loan Calculator use?
loan = price − down payment − trade-in; M = L·i ÷ (1 − (1 + i)^−n). Fixed-rate, fully amortizing loan with monthly compounding; excludes fees, insurance and taxes.
What do I need to enter in the auto Loan Calculator?
You enter Vehicle price ($), Down payment ($), Interest rate (APR) (%) and Term (months). Optional: Trade-in value ($).
How is the result rounded or limited?
IEEE-754 double precision; money shown to cents, rates to 4 decimals. Results are estimates, not financial advice. Down payment plus trade-in must be less than the price.
What are the limits of this calculator?
Down payment plus trade-in must be less than the price. Excludes sales tax and fees.
What is an example of a auto Loan result?
With vehicle price 30000, down payment 5000, interest rate (APR) 6 and term 60, the monthly payment is $483.32.
Can I rely on this calculator for a decision?
Results are estimates for planning, not financial advice. Lender terms, fees, taxes and rounding rules can change real figures, so confirm important numbers with your lender or a licensed adviser. For this calculator in particular: Down payment plus trade-in must be less than the price.
Related calculators
- Loan Calculator — Estimate your monthly loan payment, total interest and total cost.
- Loan Comparison Calculator — Compare the payment and total interest of two loans.
- Amortization Calculator — Full amortization schedule with optional extra monthly payments.
- Interest Rate Calculator — Annual interest rate implied by a loan amount, payment and term.
- HELOC Calculator — Interest-only draw-period payment and the repayment-period payment of a home equity line.
- APR Calculator — Annual percentage rate of a loan once upfront fees are counted.
Sources
- Standard time-value-of-money relations (e.g. Brealey, Myers & Allen, Principles of Corporate Finance)
Content last reviewed 2026-11-04. Formulas and worked examples are checked by automated tests against independently computed values.