Who this tool is for
AutoLoan Check is an independent educational tool for individual U.S. taxpayers considering the federal car loan interest deduction. It is not operated by the IRS or NHTSA, and no professional tax review is claimed.
Vehicle data
VINs are decoded using NHTSA’s free vPIC DecodeVinValues service. We display plant country, city, state, manufacturer plant name, model year, make, model, body class, and gross vehicle weight rating when provided. Only a decode with ErrorCode 0 is used for automatic vehicle checks; other results require confirmation.
A U.S. plant country supports the assembly check using the method described by IRS §1.163-16(e)(3). A foreign country fails that requirement. Missing country data stays unknown. We do not infer U.S. assembly from a brand or VIN prefix.
Weight and vehicle type
A GVWR range wholly below 14,000 lb supports a pass; a range starting at or above 14,000 fails. A range spanning the threshold stays unknown. For example, Class 3 (10,001–14,000 lb) needs the exact label rating. Body classes are mapped conservatively to permitted vehicle types. Unclear vehicle types require manual confirmation.
Tax rules
The rules are based on IRS T.D. 10054, especially §1.163-16(c)–(h), plus IRS Topic 505 and Publication 6126. The final regulation is effective November 9, 2026, with applicability to taxable years beginning after December 31, 2024 and before January 1, 2029. Its publication and effective date are different; the statute already provides the 2025–2028 window.
- Determine qualifying annual interest, excluding interest on nonqualifying financed amounts.
- Subtract interest claimed elsewhere; the same interest cannot be deducted twice.
- Limit qualified interest to $10,000 per federal return.
- Subtract $200 for every $1,000 or partial $1,000 of MAGI above $100,000, or $200,000 for a joint return.
- Floor the result at zero.
For individuals, MAGI adds exclusions under IRC §§911, 931 and 933 to AGI. All other individual filing statuses use the $100,000 threshold. The tool does not calculate AGI, tax brackets, state tax, actual refunds, or your complete return.
Refinancing and mixed-use vehicles
A refinance can qualify only to the outstanding balance of the eligible loan. Cash-out and financed negative equity require allocation. The personal-use standard is expected use exceeding 50% at loan origination. Interest otherwise deductible as business interest cannot also be counted here if already claimed elsewhere. The tool accepts a user-calculated qualifying percentage; it does not determine complex allocations.
Limits of the result
Answers about original use, dates, loan security, related-party lending, public-road requirements, and borrower continuity are self-reported. A known failure returns zero. An unknown required answer leaves eligibility unconfirmed. The calculation assumes ordinary individual filing circumstances; estates, trusts, and uncommon fact patterns need individual advice.
Maintaining the site
Guides show the actual review date rather than claiming automatic updates. Before filing, recheck official return-year instructions. New brand and model pages are only intended to be published with useful, verified evidence, not a blanket list of eligible cars.
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