ISIN Validator (International Securities Identification Number - ISO 6166)
Validate authenticity, issuer country structure, NSIN, and Luhn check digit for 12-character international ISIN codes.
About ISIN Validation
ISIN validation verifies structural correctness of the ISO 3166-1 country code, strict 12-character alphanumeric length, and algorithmic Luhn check digit matching.
Invalid ISIN codes halt automated order processing across electronic exchanges, trigger FIX protocol rejections, and cause transaction reporting failures under MiFID II and CFTC regimes.
ISIN Anatomy & Structure (ISO 6166)
An ISIN code consists of exactly 12 alphanumeric characters divided into 3 essential segments:
| Position | Field | Length | Meaning & Rule | Example |
|---|---|---|---|---|
| 1 and 2 | Country / Issuer Code | 2 letters | ISO 3166-1 alpha-2 country code of issuer or special prefix (e.g., XS for Eurobonds, EU for European Union) | US |
| 3 to 11 | NSIN (National Securities Number) | 9 characters | Local national identifier allocated by the NNA (e.g., CUSIP, SEDOL, WKN) | 037833100 |
| 12 | Check Digit | 1 digit | Decimal check digit computed using extended Luhn Modulo 10 on the transliterated string | 5 |
Integrity Algorithm (Extended Luhn Modulo 10)
Official mathematical verification executed on the 12-character ISIN:
D = (10 - (∑ S(d_i × w_i) mod 10)) mod 10
- 1. Transliterate characters: digits 0-9 remain unchanged; uppercase letters A-Z convert to two-digit numbers 10-35 (A=10, ..., Z=35).
- 2. Traverse the expanded digits from right to left.
- 3. Apply alternating weights: rightmost digit multiplied by 2, next by 1, then 2, 1, and so on.
- 4. Multiply each digit by its weight and add the digits of the resulting products.
- 5. Sum all values; the check digit is the amount required to reach the next multiple of 10.