Auto Loan Calculator
Work out your monthly car payment, total interest and payoff schedule for an auto loan, including the effect of a larger down payment or extra payments.
- Payoff time
- 5y 0m
- Number of payments
- 60
Yearly schedule
| Year | Principal | Interest | Balance |
|---|---|---|---|
| 1 | $4,236.00 | $1,846.92 | $20,764.00 |
| 2 | $4,587.59 | $1,495.33 | $16,176.41 |
| 3 | $4,968.36 | $1,114.56 | $11,208.05 |
| 4 | $5,380.73 | $702.19 | $5,827.33 |
| 5 | $5,827.33 | $255.59 | $0.00 |
Estimate. Excludes taxes, insurance and fees.
What This Auto Loan Calculator Does
This auto loan calculator estimates your monthly car payment, the total interest you'll pay over the life of the loan, and your full payoff amount. Enter the vehicle price, your down payment and trade-in value, the annual interest rate (APR), and the loan term in months.
It's built for anyone shopping for a car, comparing dealer financing against a credit union offer, or deciding whether a 48-, 60-, or 72-month term fits their budget. By rolling in sales tax and fees, the car payment calculator shows the real amount you'll finance, not just the sticker price.
How the Calculation Works (The Formula)
Auto loans use standard amortization, the same math behind most fixed-rate loans. The monthly payment is calculated with this formula:
M = P x [ r(1 + r)^n ] / [ (1 + r)^n - 1 ]
Here, M is the monthly payment, P is the loan principal (the amount you actually borrow), r is the monthly interest rate (annual APR divided by 12), and n is the total number of payments (months in the term). The principal P equals the vehicle price plus sales tax and fees, minus your down payment and trade-in value.
A Worked Example With Real Numbers
Suppose you buy a car priced at $30,000 with a 6% sales tax ($1,800) and $400 in fees. You put $3,000 down and trade in a vehicle worth $2,200. Your financed principal is $30,000 + $1,800 + $400 - $3,000 - $2,200 = $27,000.
With a 7% APR over 60 months: r = 0.07 / 12 = 0.0058333, and n = 60. Plugging into the formula gives a monthly payment of about $534.59. Over 60 months you pay roughly $32,075 total, meaning about $5,075 in interest on the $27,000 you borrowed.
How Term Length and Down Payment Change the Result
Two inputs move the numbers the most: the loan term and your upfront cash.
A longer term lowers the monthly payment but raises total interest, because you're paying interest for more months. A larger down payment or trade-in shrinks the principal, cutting both the payment and the interest.
- Same $27,000 at 7% over 72 months: about $460/month, but roughly $6,143 in total interest, over $1,000 more than the 60-month plan.
- Adding $2,000 more down (financing $25,000) at 7% over 60 months drops the payment to about $495 and saves around $400 in interest.
- A 1-point lower APR (6% instead of 7%) on $27,000 over 60 months saves roughly $730 in interest over the loan.
Tips and Common Mistakes
Use these guidelines to make the estimate match your real loan offer and avoid costly surprises.
- Compare total interest, not just the monthly payment. A low payment from a 72- or 84-month term often hides thousands in extra interest.
- Confirm whether tax and fees are rolled into the loan. Financing them adds to the principal and the interest you pay.
- Watch for negative equity: if your trade-in is worth less than you still owe on it, that gap gets added to the new loan.
- Enter the APR, not a promotional 'rate', and check that there's no prepayment penalty if you plan to pay early.
- Get pre-approved before visiting the dealer so you have a benchmark rate to negotiate against.