Car loan interest is not deductible for most people, even if you itemize deductions on your tax return
The short answer: if you borrowed money to buy a car for personal use — commuting, errands, family trips — the interest you pay is not deductible. The IRS treats personal car loans the same way it treats credit card debt or a personal loan. You pay it with after-tax dollars, and you cannot write it off.
The only exception is narrow and specific. If you borrowed money to buy a car that you use for business purposes — not commuting to a job, but actually running a business — then you may be able to deduct the interest. A rideshare driver, a plumber with a work vehicle, or a consultant who uses a car as a mobile office might may have access to. But the car must be used primarily for business, and you need to track that usage carefully.
This rule has been in place since 1986, when Congress eliminated the deduction for personal interest as part of a major tax overhaul. It applies whether you have a new car loan, a used car loan, or a refinanced loan.
Key Takeaways
- Personal car loan interest cannot be deducted on your federal tax return, even if you itemize deductions instead of taking the standard deduction.
- Business use of a vehicle may allow you to deduct interest, but only if the car is used primarily for business and you document that usage.
- Deducting business vehicle interest requires keeping records of mileage, business purpose, and the loan documents themselves.
- If you are unsure whether your vehicle qualifies as a business asset, a tax professional can review your situation and help you determine what you can and cannot deduct.
Why personal car loan interest is not deductible
The IRS distinguishes between interest on money borrowed for investment or business purposes and interest on money borrowed for personal consumption. Personal car loans fall into the consumption category — you are borrowing to buy something you will use personally, not to generate income or build a business asset.
This is different from, say, a mortgage on a rental property. If you borrow money to buy a house that you rent out, the interest on that loan is deductible because the property generates income. A car you drive yourself does not generate income, so the interest is not deductible.
The rule applies regardless of how much interest you pay or how long your loan term is. A five-year car loan with thousands of dollars in interest still does not may have access to.
When business vehicle interest might be deductible
If you own a business and use a vehicle primarily for business purposes, you may be able to deduct the interest on the loan. This applies to self-employed people, sole proprietors, and business owners who borrow to purchase a work vehicle.
The key word is "primarily." The IRS wants to see that the vehicle is used more than half the time for business. If you use a truck 60 percent of the time for your contracting business and 40 percent for personal use, you might deduct 60 percent of the interest. But if you use it 40 percent for business and 60 percent for personal use, you cannot deduct any of it.
Commuting to a job does not count as business use, even if you work for yourself. The IRS treats commuting as personal use. However, if you drive from one job site to another during the workday, or if you carry equipment or clients in the vehicle as part of your business, that counts as business use.
How to document business vehicle use for tax purposes
If you think your vehicle qualifies for a business interest deduction, you need to keep detailed records. The IRS expects to see a mileage log that shows the date, destination, business purpose, and number of miles driven for each trip. You do not need to log every single trip, but you should have enough entries to establish a pattern and support your percentage of business use.
You also need to keep the loan documents themselves — the promissory note, the payment history, and proof of interest paid. Your lender will send you a Form 1098-T or a statement showing the interest paid during the tax year. Keep that document with your tax records.
If you are audited and cannot produce a mileage log or other documentation, the IRS will disallow the deduction. The burden of proof is on you to show that the vehicle was used for business.
The difference between deducting interest and deducting vehicle expenses
Even if you cannot deduct the interest on your car loan, you may be able to deduct other vehicle expenses if you use the car for business. These include fuel, maintenance, repairs, insurance, and registration fees. You can deduct these either by tracking actual expenses or by using the IRS standard mileage rate, which changes each year.
The standard mileage rate is simpler for most people. You multiply the number of business miles driven by the rate set by the IRS for that year. The rate includes an allowance for depreciation, fuel, maintenance, and other costs — but it does not include loan interest. So even if you use the standard mileage rate, the interest on your car loan is still not deductible.
If you track actual expenses instead, you can deduct fuel, insurance, maintenance, and depreciation, but again, not the interest on the loan itself.
What happens if you refinance your car loan
Refinancing does not change the deductibility of the interest. If the car is used for personal purposes, the interest on the new loan is not deductible. If the car is used for business, the interest on the refinanced loan may be deductible, just as the interest on the original loan was.
When you refinance, you are essentially paying off the old loan with a new loan. The IRS looks at the use of the vehicle, not the age or terms of the loan. So refinancing a personal car loan does not suddenly make the interest deductible.
Frequently Asked Questions
Can I deduct car loan interest if I use my car for work?
Only if you use the car for business purposes — not commuting to a job. If you are self-employed and use the car to meet clients, carry equipment, or travel between job sites, you may deduct a portion of the interest based on the percentage of business use. Commuting is always considered personal use, even for self-employed people.
What if I use my car for both personal and business purposes?
You can deduct the interest only on the portion of the loan that corresponds to business use. If you use the car 70 percent for business and 30 percent for personal use, you could deduct 70 percent of the interest. You need to document this with a mileage log and keep records of your business trips.
Does the type of car matter — like a truck or van versus a sedan?
The type of vehicle does not matter. The IRS rule applies to all personal vehicles. However, if you use a truck or van primarily for business, the same deduction rules explore: you can deduct the interest based on business use percentage, provided you document it.
If I cannot deduct the interest, can I deduct the principal payments on my car loan?
No. Principal payments are not deductible under any circumstances. You are paying back money you borrowed; that is not a tax-deductible expense. Only the interest portion of your payment might be deductible, and only if the vehicle is used for business.
Should I talk to a tax professional about my situation?
If you use a vehicle for business and want to deduct expenses, a tax professional can review your situation and help you determine what you can deduct and what records you need to keep. They can also help you decide whether to use the standard mileage rate or track actual expenses, which method saves you more money.