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.
Frequently Asked Questions (FAQ)
Does this tool verify if an employer is officially registered with the DEL?
No. This tool performs mathematical and structural validation (Luhn checksum) without connecting to private government databases.
Are the 'U' prefix and slash '/' mandatory?
No. The validator accepts unformatted digits (12345674), slash-separated (1234567/4), or prefixed format (U1234567/4).
Why does South Africa use the Luhn algorithm for UIF/COIDA?
The Luhn algorithm provides immediate detection of accidental transposition errors and single-digit typos in payroll forms.