Portugal NISS Generator
Portuguese Social Security Identification Number (NISS) of 11 digits. QA.
Waiting for generation...
About the Portugal NISS
The NISS is the unique 11-digit identification code issued by the Portuguese Social Security to manage social contributions, typically starting with prefix 1.
This tool generates and validates NISS codes, checking check digits using the official weighted Modulo 11 calculation.
Anatomy & Structure of Portuguese NISS
The Social Security Identification Number (NISS) comprises 11 digits regulated by ISS:
| Position | Field | Length | Meaning & Rule | Example |
|---|---|---|---|---|
| 1 | Beneficiary Category | 1 digit | Identifier category (1 for Individual Worker, 2 for Corporate Employer) | 1 |
| 2 to 10 | Sequential | 9 digits | Correlative record sequential in Social Security database | 234567890 |
| 11 | Check Digit | 1 digit | Weighted checksum using prime multipliers [29, 23, 19, 17, 13, 11, 7, 5, 3, 2] | 8 |
NISS Validation Algorithm (Prime Multipliers Checksum)
Social Security applies a weighted formula using 10 prime factors and complement to 9:
DV = 9 - (sum(d_i * [29, 23, 19, 17, 13, 11, 7, 5, 3, 2]) % 10)
- 1. Multiply each of the first 10 digits by prime weights [29, 23, 19, 17, 13, 11, 7, 5, 3, 2].
- 2. Compute sum of products.
- 3. Determine remainder modulo 10: Remainder = Sum % 10.
- 4. Subtract remainder from 9: DV = 9 - Remainder.
- 5. Verify match against the 11th digit.