Japan Individual My Number Generator
Generate and format valid Japan Individual My Number for software testing and development.
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About Japan Individual My Number
My Number (Individual Number / 個人番号) is the 12-digit social security and tax identification number in Japan.
Composed of 12 digits, where the 12th digit is calculated using the official weighted modulus formula defined by Japanese ministerial ordinance.
Anatomy & Structure of My Number (マイナンバー / Individual Number)
The Japanese Individual Number consists of 12 numeric digits in 2 parts:
| Position | Field | Length | Meaning & Rule | Example |
|---|---|---|---|---|
| 1 to 11 | Base Individual Number | 11 digits | Unique sequence assigned by J-LIS to residents in Japan | 12345678901 |
| 12 | Check Digit | 1 digit | Calculated via weighted Modulo 11 (MIC Ministerial Ordinance No. 85/2014) | 2 |
Official Algorithm (Weighted Modulo 11 — MIC No. 85/2014)
Official check digit calculation for Japan My Number:
S = Σ P[n] × Q[n]; R = S mod 11; DV = R <= 1 ? 0 : 11 - R
- 1. Number the first 11 digits from n=1 (rightmost) to n=11 (leftmost).
- 2. For 1 <= n <= 6, weight is Q[n] = n + 1 (weights: 2, 3, 4, 5, 6, 7).
- 3. For 7 <= n <= 11, weight is Q[n] = n - 5 (weights: 2, 3, 4, 5, 6).
- 4. Compute weighted sum S and remainder R = S mod 11.
- 5. If R is 0 or 1, check digit is 0; otherwise DV = 11 - R.