How to tell where your car was assembled from its VIN

Why the assembly plant matters

For the 2025–2028 car loan interest deduction, a vehicle only qualifies if its final assembly took place in the United States. The regulation defines final assembly as the process by which a manufacturer produces the vehicle at a plant, factory or other place from which it is delivered to a dealer with all the parts needed for it to run [1].

You do not have to trace a supply chain to prove it. The rule gives two things you may rely on: the vehicle’s plant of manufacture as reported in the VIN, or the final assembly point reported on the label affixed to the vehicle [1]. This guide shows how to read both. The details of the deduction itself are in The car loan interest deduction, explained.

The 17 characters of a VIN

A vehicle identification number is 17 characters long, and a federal standard — 49 CFR Part 565 — fixes what each part means [2]. You will find it on the dashboard near the windshield, on the driver’s door-jamb label, and on your title and loan papers.

One detail trips people up: the plant character in position 11 is the manufacturer’s own code. The standard only says that position represents the plant; which letter stands for which plant is up to each manufacturer. So you need that manufacturer’s list to read it — and NHTSA’s decoder does the lookup for you.

One model, two plants

The clearest way to see why position 11 matters is to compare two vehicles that look identical on the dealer’s lot. Both VINs below are 2026 Toyota RAV4s. We decoded both with NHTSA’s public decoder on 30 September 2026 [4]:

Same make, same model, same model year, same weight class — NHTSA reports both as “Class 1C: 4,001 – 5,000 lb”. One passes the assembly test for the deduction and the other fails it. Nothing about the badge, the brochure or the price tells you which one you are buying; the VIN does.

Which VIN character shows the country — and why it doesn’t decide it

A common shortcut says “VINs starting with 1, 4 or 5 were made in the USA”. That shortcut reads the manufacturer identifier in positions 1–3. The federal standard says those characters identify the manufacturer and type of the vehicle [2]; it is position 11 that the standard assigns to the plant of manufacture. Manufacturers with plants in several countries use several identifiers, and the identifier is not a statement about where a particular vehicle was put together.

The shortcut also misses US plants whose identifiers start with other characters. NHTSA’s list registers Tesla’s 7SA and Rivian’s 7PD to the United States, and NHTSA decodes VINs with those identifiers to plants in Austin, Texas and Normal, Illinois [5].

Very often the first character and the plant point to the same country — in the RAV4 pair above, the Kentucky vehicle starts with “4” and the Ontario one with “2”. But the rule you rely on for the deduction is the plant of manufacture or the final assembly point on the label, not the first character. When money depends on it, read position 11 through the decoder, or read the label.

Checking with NHTSA’s decoder

The National Highway Traffic Safety Administration runs a free VIN decoder built on the data manufacturers file with it. The IRS itself points to it: the preamble to the final rules says the VIN and NHTSA’s lookup tool can be used to check the weight rating and whether final assembly occurred in the United States [1].

1. Open the decoder at vpic.nhtsa.dot.gov/decoder and enter all 17 characters.
2. Find the Plant Information section at the bottom of the results; NHTSA’s own instructions point there [6]. The detailed table lists the same plant as Plant City, Plant State and Plant Country. For the deduction, the plant country has to be the United States.
3. While you are there, note the gross vehicle weight rating class. The rating must be less than 14,000 pounds; a class shown as “10,001 – 14,000 lb” includes vehicles rated at exactly 14,000, which do not qualify — check the door-jamb label for the exact figure.
4. If the decoder shows no plant, or reports an error, do not guess. Use the label described below if your vehicle has one, and keep a copy of what you relied on.

Our Does My Car Qualify? checker does these steps for you: it sends only the VIN to NHTSA’s public decoder and reads the plant and weight class from the answer.

The label on the vehicle

New passenger motor vehicles carry a parts-content label required by 49 CFR Part 583, often printed as part of the window sticker. Among other things it must state the Final Assembly Point as city, state and country [3]. That line is the second thing the deduction rule lets you rely on.

The same label carries figures that are easy to confuse with it:

• U.S./Canadian parts content — a percentage of parts by value for the whole carline. A high percentage does not mean the vehicle was assembled in the United States.
• Major sources of foreign parts content — other countries that supplied parts.
• Country of origin of the engine and of the transmission — also not the assembly point.

Only the Final Assembly Point line answers the question the deduction asks. Keep a photo of the label with your purchase papers.

The check digit: catching typos

Position 9 exists to catch transcription mistakes — and because the deduction requires the VIN on your tax return, a typo there matters. The standard gives each letter a number — A = 1 to H = 8, then J = 1 to N = 5, P = 7 and R = 9, then S = 2 to Z = 9, with no values for I, O or Q — multiplies every character by a fixed weight for its position, adds the results and divides by 11. The remainder is the check digit, and a remainder of 10 is written “X” [2].

If you mistype one character, the check digit usually stops matching — but not always: characters with the same value, such as 1, A and J, can swap without changing it. A VIN that fails the check should be fixed before you rely on any decode of it — our checker flags that and never marks such a VIN as qualifying.

This guide explains how to read a VIN; it is not tax or legal advice. The deduction depends on more than the assembly plant — see the full rules — and on your own records.