Auto Loan Calculator

Your monthly car payment is calculated using the same amortization formula as a mortgage: M = P[r(1+r)^n] / [(1+r)^n - 1], where P is the loan amount after down payment, r is the monthly interest rate, and n is the number of monthly payments. For a $30,000 loan at 6.5% APR over 60 months, the monthly payment comes to approximately $587. This formula ensures each payment covers both interest and a portion of the principal.

The total cost of the vehicle extends well beyond the sticker price and your monthly payment. Over a 60-month loan at 6.5%, a $30,000 loan accumulates roughly $5,200 in total interest, making the true cost $35,200. Adding sales tax (which varies by state from 0% to over 10%), dealer documentation fees ($200-$1,000), and registration fees reveals that a $35,000 vehicle can easily cost $42,000 or more by the time you make your final payment. This calculator shows you the full picture so you can budget accurately.

Interest rates on used car loans are typically 1-2 percentage points higher than new car loans because used vehicles depreciate faster and carry more risk for lenders. As of recent data, average new car loan rates range from 5% to 7% for borrowers with good credit, while used car loans average 7% to 9%. Manufacturer financing deals on new cars can sometimes offer promotional rates as low as 0-2.9% for qualified buyers.

A certified pre-owned (CPO) vehicle can offer a middle ground, with rates typically between new and used car loans. CPO vehicles come with manufacturer-backed warranties and undergo multi-point inspections, which reduces the risk for both the buyer and the lender. When comparing a $25,000 used car at 8% versus a $35,000 new car at 4%, the monthly payments may be surprisingly close, but the total costs over the loan term tell a very different story. Always compare total cost, not just monthly payments, when deciding between new and used.

Choosing a longer loan term lowers your monthly payment but significantly increases the total interest you pay. A $30,000 auto loan at 6.5% costs about $4,200 in interest over 48 months versus roughly $6,600 over 72 months — a difference of $2,400. Longer terms also increase the risk of being "upside down" on your loan, meaning you owe more than the vehicle is worth during the early years.

Negative equity is a particularly dangerous trap with longer auto loans. A new car loses roughly 20% of its value in the first year and 60% over five years. On a 72-month loan with a small down payment, you may owe more than the car is worth for the first 3-4 years. If you need to sell or trade the vehicle during that period, you would need to pay the difference out of pocket or roll the negative equity into your next loan, creating a cycle of debt that becomes increasingly difficult to escape. Financial experts recommend keeping auto loan terms at 48-60 months maximum.

Securing the lowest possible rate starts with checking your credit score and shopping multiple lenders before visiting a dealership. Credit unions often offer rates 1-2% lower than traditional banks or dealer financing. Getting pre-approved gives you negotiating leverage and a clear budget. Keeping the loan term to 48 or 60 months and making a down payment of at least 20% also helps you qualify for better rates.

Your credit score is the single biggest factor in the rate you receive. Borrowers with scores above 750 qualify for the best rates, often 2-3 percentage points lower than borrowers in the 600-650 range. On a $30,000 loan over 60 months, the difference between a 5% rate and an 8% rate is over $2,500 in total interest. If your score is below 700, consider spending 3-6 months improving it before applying — paying down credit card balances below 30% utilization and correcting any errors on your credit report are the fastest ways to boost your score.