Key points
- Every letter is converted to the numerical value specified in Section C.
- Each VIN position has a fixed weight; position 9 is excluded from the sum.
- Products are totalled and divided by 11.
- Remainders 0–9 produce the same digit; remainder 10 produces X.
Step 1: convert each character to a number
Digits keep their numerical value. Letters use the values listed in Annex II, Part 2, Section C, rather than their normal position in the alphabet.
For example, A and J both have the value 1; B, K and S have the value 2; R and Z have the value 9.
Step 2: apply the fixed position weights
The values in positions 1–8 are multiplied by 8, 7, 6, 5, 4, 3, 2 and 10. Positions 10–17 are multiplied by 9, 8, 7, 6, 5, 4, 3 and 2.
Position 9 is reserved for the result and is not included in the calculation.
Step 3: total, divide by 11 and use the remainder
Add all 16 weighted products and divide the total by 11. The remainder determines the check digit.
Remainders from 0 through 9 produce the corresponding digit. A remainder of 10 is represented by X.
Why valid input still matters
A mathematically correct check digit does not make an otherwise incorrect VIN compliant. The source WMI, VDS and VIS must follow the manufacturer’s approved structure.
The final four VIS characters must be numeric, I, O and Q must not appear, and the completed VIN must remain unique.
VIN letter values
| Character | Value |
|---|---|
A · J | 1 |
B · K · S | 2 |
C · L · T | 3 |
D · M · U | 4 |
E · N · V | 5 |
F · W | 6 |
G · P · X | 7 |
H · Y | 8 |
R · Z | 9 |
Position weights
Remainder to check digit
ManageVIN is a calculation and record-management aid. It does not assign WMI codes and does not replace an approval authority or professional compliance review.
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