South Africa UIF / COIDA Reference Validator
Validate South African UIF / COIDA employer reference numbers online with Luhn Modulo 10 check digit verification and 8-digit structure analysis.
How South African UIF / COIDA Validation Works
The UIF / COIDA reference consists of a 7-digit registration sequence issued by the Department of Employment and Labour and a final check digit calculated using the Luhn algorithm.
Our online validator cleans optional formatting (such as '/' and prefix 'U') and tests the Luhn Modulo 10 checksum to confirm the authenticity of the reference.
UIF / COIDA Reference Anatomy
Composition of the South African employer reference number:
| Position | Field | Length | Meaning & Rule | Example |
|---|---|---|---|---|
| 1 to 7 | Sequential Reference | 7 digits | Base employer registration sequence assigned by the Department of Labour | 1234567 |
| 8 | Check Digit (CD) | 1 digit | Checksum digit verified via Luhn Modulo 10 algorithm | 4 |
Verification Algorithm (Luhn Modulo 10)
Mathematical checksum logic applied during validation:
Luhn Checksum: Σ(weighted digits with alternating x1 and x2 parity) mod 10 = 0.
- 1. Remove 'U' prefix, slashes, and non-numeric characters.
- 2. Verify exact length of 8 decimal digits.
- 3. Reject sequences where all digits are identical.
- 4. Calculate Luhn checksum to validate the 8th check digit.