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How to Calculate APR on a Car Loan

How to Calculate APR on a Car Loan
Kevin Brouillard
Kevin BrouillardUpdated March 8, 2023
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The annual percentage rate or APR on a car loan indicates how much it costs to borrow money to buy a car. The lower the annual percentage rate for cars, the cheaper it is to borrow money. Knowing how to calculate APR on a car loan can help you compare loans and determine which option is best for your budget. Some lenders may offer 0% APR financing. This is a legitimate car loan with the interest rate fixed at 0% and no upfront fees. Other lenders may offer subprime auto loans with the APR exceeding 13% on a new car loan. Below we highlight what you need to know about calculating auto loan APRs.

What Is APR?

APR is the total annual cost to borrow money, including interest and fees, represented as a percentage. It also accounts for any dealer fees, rebates, or costs incurred by the borrower when obtaining any loan, including an auto loan.Sometimes a loan’s APR and interest rate may get mixed up since they’re both expressed as a percentage. The key difference is that a car loan interest rate is simply a percentage of the principal (the amount borrowed), whereas the APR accounts for fees and additional costs of borrowing money, as well as the interest. For example, the interest rate for a car loan might be 5%. But once various fees and costs are factored in, the APR might be 5.25%.APR is a better metric for gauging the cost of borrowing than interest rate alone. Even if two lenders offer the same interest rate and repayment term on a loan, the difference in their fees and extra charges will be revealed in the APR. Comparing APRs can help you find the right auto loan financing for you when shopping around for a car loan.Before moving on to how to calculate APR on a car loan, it might be helpful to review our comprehensive guide to auto loan terms.

Calculating Your Car Loan’s APR

Knowing how to calculate APR for car loans can be of use when assessing financing options.Lenders are generally required by federal law to disclose the APR and other loan terms before a borrower signs the loan agreement. Still, preparing beforehand can help you determine how a car loan aligns with your budget and financial goals.Below we highlight how to calculate APR on a car loan:

1. Gather Key Information

Before diving into the actual arithmetic of how to calculate APR for car loans, you’ll need to collect the following information:
  • Principal. This is the amount of money borrowed. When you’re calculating car loan APR, you can think of car loan principal as the price of the car minus your down payment and the value of a trade-in vehicle (if you traded one in).
  • Interest rate. This represents the percentage charged on top of the principal each year. In your DIY calculation, this may be an estimated value. The best interest rate on a car loan can be as low as 0%.
  • Loan term. This is the length of the auto loan, usually expressed in months or years. Borrowers can have long-term auto loans greater than 72 months, or short-term auto loans as low as 12 months.
  • Fees. Any additional costs, such as origination fees, are factored into the APR, so you’ll need to know what those are, too.
  • Taxes. Applicable state, county, and city sales taxes can be rolled into a car loan.

2. Run the APR Equation

Once you have the details above, the following formula can calculate APR for a car loan:APR = [(I/P/T) x 365] x 100
  • I = Interest, taxes, and fees
  • P = Principal
  • T = Term (in days)
For this example APR calculation, we’ll give the interest amount, fees, and taxes a combined value of $5,000. The principal is $25,000, and the loan term is 60 months (or 1,825 days). APR = [($5,000/$25,000/1,825) x 365] x 100APR = 4%Some lenders may provide an auto loan calculator to crunch the numbers for you. Typically, you input the borrowed amount, interest rate, loan term, and other information to get APR and monthly payment estimates.There are other factors that may impact APR with car loans, but this formula can offer a ballpark figure for your reference.

How Do Auto Lenders Calculate APR?

The method for figuring out what APR to offer on a car loan can differ among lenders. But while the loan terms and approval are ultimately up to the individual lender, these are some key APR components that may be considered:

Down Payment

The amount of money you put down for an auto loan could help secure a lower interest rate, and thus, a lower APR. Trading in your old vehicle can be a convenient way to fund a car loan down payment. You can check online sites like CARFAX® or Autotrader® to get an estimate on your trade-in’s value.

Vehicle Age and Condition

If you’re buying a used car, lenders can evaluate a car’s manufacture date, mileage, and general wear and tear when calculating car loan APR. Typically, newer cars fetch lower rates than older vehicles. Some lenders may be unwilling to finance a high-mileage used car purchase.

Loan Term

Loans with longer terms may have higher interest rates than loans with shorter terms. If the lender allows, paying off a car loan early can reduce the overall amount of interest you’d pay during the life of the loan.

Personal Financial Situation

Auto lenders could consider personal financial information, such as how long you’ve been employed and your debt-to-income ratio (DTI) when calculating what APR to offer you. Lenders generally like to see a DTI below 36%.

Credit History

A borrower’s credit report may play a large part in the APR of the loan he or she can get. Buyers with excellent credit could even qualify for 0% APR financing on a new car purchase.

Fixed vs Variable APR

Lenders can offer fixed- or variable-rate financing.Fixed-rate auto loans have consistent payments for the entire loan term, meaning that you can project how much interest you’ll pay each month.Alternatively, the APR for variable-rate loans can fluctuate as the interest rate changes according to index changes. The APR could increase or decrease over the life of the loan. If you’re unhappy with the APR on your car loan, you may explore auto refinancing or find someone to take over your car loan.Recommended: Can Someone Take Over My Car Loan?

Average Auto Loan APRs for Different Credit Scores

Are you concerned about whether you can get subprime auto loans for bad credit? Fret not: There are some auto loan financing options available to borrowers with poor credit scores between 300 and 600.Your credit score, however, may impact your chances of getting a good car loan interest rate and APR. Borrowers with super prime credit had an average new car loan rate of 4.75% compared with 13.42% for borrowers with deep subprime credit in the fourth quarter of 2022.While interest rate isn’t as comprehensive as APR, it’s the major component in APR and can illustrate how much rates may vary by credit score. Using Experian data released in March 2023, here’s a breakdown of average auto loan interest rates by credit score and car type:
Credit scoreAverage new car loan rateAverage used car loan rate
Super prime: 781–8504.75%5.99%
Prime: 661–7805.82%7.83%
Nonprime: 601–6608.12%12.08%
Subprime: 501–60010.79%17.46%
Deep subprime: 300–50013.42%20.62%
Having a solid credit score can help reduce the overall cost of borrowing money. Checking your credit score beforehand can help you know where you stand before approaching lenders for an auto loan.When they’re looking at car loan applications, lenders may use a FICO® Auto Score that places greater emphasis on auto-loan-oriented behavior and risk than does a regular FICO Score. If you’ve stayed current on car payments for the past seven years, your FICO® Auto Score may be in better shape.Other traditional creditworthiness factors like repayment history and number of accounts are still important, too.

The Takeaway

Understanding how to calculate APR on a car loan is useful when you’re evaluating financing options. Knowing how lenders calculate APR can help you negotiate car loan financing that’s right for you.If you’re looking to refinance your car loan, Lantern by SoFi can help. Simply by filling out one online form, you’ll be able to compare auto refinancing options from multiple lenders.Find and compare auto loan refinance options with Lantern.

Frequently Asked Questions

Is a 0% APR car loan worth it?
How does auto refinancing affect your car loan APR?
Does a down payment lower your APR?
Photo credit: iStock/Chainarong Prasertthai

About the Author

Kevin Brouillard

Kevin Brouillard

Kevin Brouillard is a Returned Peace Corps Volunteer, educator, and personal finance writer. His work has appeared in online publications such as Earth Island Journal, Jetsetter,, and Tripsavvy. Kevin covers an array of financial topics for SoFi, including loans for students and small businesses.
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