New Auto Loan Interest Deduction vs. Section 179: Which One Applies to You?
For the first time since 1986, you can deduct interest on a personal auto loan. The One Big Beautiful Bill Act (OBBBA), signed July 4, 2025, created a brand-new federal deduction of up to $10,000 per year in auto loan interest — but only for tax years 2025 through 2028, and only for new, personal-use, U.S.-assembled vehicles. Business owners are asking the natural next question: can I claim this and Section 179? The short answer is no — they are two separate provisions for two separate kinds of vehicles. Here is exactly how they differ.
What the new auto loan interest deduction requires
The rules are narrow. Every one of these must be true:
- New vehicle only — you must be the first owner; the original use begins with you. Used vehicles, leases, and salvage titles are excluded.
- Personal use only — not business or commercial use.
- Final assembly in the United States — verify with the NHTSA VIN decoder before you buy.
- Under 14,000 lbs GVWR — cars, SUVs, vans, minivans, pickup trucks, and motorcycles all fit.
- Loan originated after December 31, 2024, secured by a lien on the vehicle, from a qualified lender (no family or related-party loans).
- You report the VIN on your tax return, and your lender sends you an annual interest statement.
It is an above-the-line deduction, so you can claim it whether you itemize or take the standard deduction. The deduction phases out once your modified adjusted gross income tops $100,000 (single) / $200,000 (joint), and disappears entirely at $150,000 / $250,000. One fresh detail: final IRS regulations (September 2026) confirm that negative equity rolled over from a trade-in is not deductible, even if it is bundled into the new loan.
Section 179: the business-vehicle version
Section 179 is the mirror image: it is for business-use vehicles and equipment. For 2026 you can expense up to $2,560,000 of qualifying property (phasing out above $4,090,000 in total purchases), with the $32,000 heavy-SUV cap and 100% bonus depreciation as permanent backup. A business vehicle’s loan interest, meanwhile, is already deductible as an ordinary business expense — business owners never needed the new provision.
Side-by-side comparison
| New auto loan interest deduction | Section 179 | |
|---|---|---|
| Vehicle use | Personal only | Business (>50%) |
| Vehicle age | New only | New or used |
| Assembly | U.S. final assembly required | No requirement |
| What it deducts | Interest paid, up to $10,000/year | Purchase price, up to $2,560,000 |
| Income limits | Phaseout $100k/$200k MAGI | None (limited by business income) |
| Years available | 2025–2028 only | Permanent |
| Itemizing required? | No | N/A (business deduction) |
Can you claim both?
Not on the same vehicle. The auto loan interest deduction explicitly excludes business and commercial use, and Section 179 requires more than 50% business use — the two provisions are mutually exclusive by design. If you run a business and buy a work truck, you use Section 179 (plus bonus depreciation) on the purchase price and deduct the loan interest as a business expense. The new $10,000 deduction is aimed at everyone else: W-2 employees and families financing a personal car, who had zero deduction for auto loan interest before 2025.
Worked comparison: $50,000 pickup, financed
Take a $50,000 pickup financed with a $45,000 loan at 7% for 72 months. First-year interest is roughly $3,000.
- Personal use (new, U.S.-assembled): deduct up to $3,000 of interest — worth about $660 in tax savings at a 22% marginal rate. Nothing to deduct on the purchase price itself.
- 100% business use (over 6,000 lbs GVWR, 6-ft-plus bed): expense the full $50,000 under Section 179 — worth about $11,000 at the same 22% rate — plus deduct the $3,000 of interest as a business expense.
They are not really competitors; they serve different buyers. The trap to avoid is buying a vehicle for the business and assuming the new personal deduction adds on top — it does not. Run your scenario in the vehicle calculator first, and if the truck is for work, read how financing interacts with the tax savings before you sign.
One more angle: EVs
A new, U.S.-assembled EV bought for personal use qualifies for the interest deduction even where depreciation rules are stingy — a Tesla Model Y falls under the luxury-auto caps for business depreciation, but its owner’s loan interest can still qualify for the new personal deduction. Different provision, different vehicle, different rulebook.
Buying for the business? Run the Section 179 math first.
Enter the price, business-use percentage, and vehicle class to see your first-year write-off.
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