New vs used, leases and refinancing
Most people who lose this deduction lose it here rather than on the car itself. Four traps, one rule each, and a worked example of every one.
Trap 1: a used car, however American it is
The rule: original use must begin with you - you have to be the first person to take delivery after the vehicle is sold, registered or titled.
Example: a 2024 Ford F-150 assembled in Dearborn, Michigan, bought in 2026 with 22,000 miles on it. The car passes the assembly, weight and type tests. It still fails, because somebody else's use came first. The clue is on your purchase documents: if your loan is written as a used-vehicle loan, it is not a qualifying loan.
The flip side: a brand-new previous-model-year vehicle sold new in 2026 does qualify. "New" is about the first use, not the model year.
Trap 2: a lease, and the buyout that follows it
The rule: lease payments are not interest on a qualifying vehicle loan, and buying out your own lease generally fails the "new" test because original use began with the lessor.
Example: a 3-year lease on a US-assembled truck, then a buyout at the end. Neither the lease payments nor the buyout financing produces a deduction. The same applies if you took over somebody else's lease.
The one route that can work is a straight purchase of a new vehicle by you, financed from day one, with a first lien in your name.
Trap 3: refinancing past the limits
The rule: refinancing a qualifying loan keeps qualifying if the new loan is secured by a first lien on the same vehicle - but only up to the outstanding balance at the refinance date, and only for the remaining term of the loan being refinanced.
| What happens | Does it still qualify? |
|---|---|
| Refinancing the same balance at a lower rate | Yes |
| Extending the term to lower the payment | Interest on the refinanced balance only, and only while inside the 2025-2028 window |
| Taking cash out | The cash-out element does not qualify |
| Refinancing a loan for a used car | No - the original loan never qualified |
Trap 4: what was financed alongside the car
The rule: interest on amounts financed for things that are not the vehicle - a trailer, a boat, an unrelated purchase - is not qualifying interest.
Example: a single loan covering a new pickup and a boat trailer. Only the interest attributable to the truck counts. Ordinary vehicle-purchase items such as sales tax, registration fees and a service contract can be part of the financed amount; the regulations then decide how payments are allocated if part of the loan is non-qualifying.
Negative equity rolled in from a previous loan is handled by the ordering rules in the regulations and depends on your contract. We flag it rather than calculate it - that is a job for your tax professional.
The short version
- New means new to the world, not new to you.
- Leases are out; so is buying out your own lease.
- Refinancing is fine within the old balance and the old term; cash-out is not.
- Cash purchases have no interest, so there is nothing to deduct.
- Fleet sales, salvage-title vehicles, cars bought for parts and loans from related parties are all excluded.
Common questions
What counts as "new" for this deduction?
Not the model year. A vehicle is new if your use is the first use after it is sold, registered or titled. A 2025 model bought new in 2026 qualifies; a 2026 model that somebody else drove home first does not.
Does a dealer demonstrator or a "new" loaner with 2,000 miles qualify?
Generally not. If the dealer used it as a demonstrator before you took delivery, your use is not the first use, and the loan documents usually describe it as used. The regulations are explicit that original use has to begin with you.
Can I deduct interest after refinancing my qualifying loan?
Yes, within limits. A refinance of a qualifying loan keeps qualifying if it is secured by a first lien on the same vehicle - but only up to the outstanding balance at the refinance date and the remaining term of the loan being replaced. Amounts above that, such as cash taken out, do not qualify.
What happens if I rolled negative equity into the new loan?
That portion is not for the purchase of the new vehicle, so interest attributable to it is not a qualifying payment in general. The regulations deal with the ordering of payments; your lender's contract decides the detail, so check with a tax professional before claiming the full figure.
What if I paid cash?
There is no interest, so there is nothing to deduct. The deduction is for interest on a loan, not for buying a car.
Check a VIN Estimate the deduction
Sources for this guide
- T.D. 10054, final regulations under 26 CFR §1.163-16 and §1.6050AA-1, 91 FR (September 8, 2026); effective November 9, 2026 — accessed 2026-10-07.
- IRC §163(h)(4), added by the One Big Beautiful Bill Act of 2025, Pub. L. 119-21, §70203 (the car loan interest deduction) — accessed 2026-10-07.
- IRS Topic No. 505, Interest expense — accessed 2026-10-07.
We link to primary sources: the statute, the regulations, IRS forms and instructions, and NHTSA's own vehicle data. Where those sources do not settle a question, we say so rather than guess.