How the VIN check digit (position 9) is calculated
Updated 2026-10-05 · By the VINready team, built by a Canadian trailer manufacturer
The 9th character of every VIN is a check digit. It’s calculated from the other 16 characters, so a single mistyped character almost always shows up as a mismatch. Here’s the calculation, the same one VINready runs for every VIN it issues and that the free VIN checker runs in your browser.
Step 1: turn each character into a number
Digits keep their value. Letters get these values (I, O and Q are never used):
| A | B | C | D | E | F | G | H | J | K | L | M | N | P | R | S | T | U | V | W | X | Y | Z |
|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|
| 1 | 2 | 3 | 4 | 5 | 6 | 7 | 8 | 1 | 2 | 3 | 4 | 5 | 7 | 9 | 2 | 3 | 4 | 5 | 6 | 7 | 8 | 9 |
Step 2: multiply by each position’s weight
Each position has a fixed weight: 8 7 6 5 4 3 2 10 0 9 8 7 6 5 4 3 2. Position 9 has weight 0, because it’s the one being worked out. Multiply each character’s value by its weight and add them up.
Step 3: divide by 11 and keep the remainder
The remainder (0–10) is the check digit. A remainder of 10 is written as X.
Worked example: XX9ZAFCLXV1123001
| Position | 1 | 2 | 3 | 4 | 5 | 6 | 7 | 8 | 9 | 10 | 11 | 12 | 13 | 14 | 15 | 16 | 17 |
|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|
| Character | X | X | 9 | Z | A | F | C | L | X | V | 1 | 1 | 2 | 3 | 0 | 0 | 1 |
| Value | 7 | 7 | 9 | 9 | 1 | 6 | 3 | 3 | – | 5 | 1 | 1 | 2 | 3 | 0 | 0 | 1 |
| Weight | 8 | 7 | 6 | 5 | 4 | 3 | 2 | 10 | 0 | 9 | 8 | 7 | 6 | 5 | 4 | 3 | 2 |
| Product | 56 | 49 | 54 | 45 | 4 | 18 | 6 | 30 | 0 | 45 | 8 | 7 | 12 | 15 | 0 | 0 | 2 |
- Sum of the products: 351.
- 351 ÷ 11 leaves a remainder of 10.
- So the check digit is X (10 is written as X), and that’s what position 9 holds.
Building a VIN? Fill in all 16 other characters first, with any placeholder in position 9, then work out the check digit last. Change any character, even the serial number, and the check digit has to be worked out again.
Common questions
- What is the 9th digit of a VIN?
- It’s the check digit: a number from 0 to 9, or X for 10, worked out from the other 16 characters. If one character is mistyped, the check digit almost always stops matching.
- Why is there an X in my VIN?
- When the calculation leaves a remainder of 10, the check digit is written as X. It’s only ever in position 9.
- Does a correct check digit mean the VIN is real?
- No, only that it’s consistent. It catches typing mistakes and made-up numbers, but it can’t tell you the vehicle exists.
This guide explains the rules in plain language and isn’t legal advice. The Motor Vehicle Safety Regulations and Transport Canada’s guidance are the final word; check them, or ask Transport Canada, before relying on a detail.