UK NINO Validator
Online UK National Insurance Number (NINO) validator. Verify DWP constraints.
How does NINO validation work?
Validation checks if the NINO has exactly 9 characters (two prefix letters, six central digits, and a final suffix A, B, C, or D).
The validator checks strict DWP constraints: first letter cannot be D, F, I, Q, U, V, or O; second letter cannot be D, F, I, Q, U, V, or O; and specific geographic/test prefixes (like BG, GB, NK, ZZ) are marked as invalid.
Anatomy & Structure of British NINO (9 Characters)
The UK National Insurance Number consists of 9 characters across 3 regulatory blocks:
| Position | Field | Length | Meaning & Rule | Example |
|---|---|---|---|---|
| 1 & 2 | Administrative Prefix | 2 letters | Alphabetic prefix issued by DWP (excluding D, F, I, Q, U, V) | |
| 3 to 8 | Personal Identifier | 6 digits | Sequential numeric registration digits | 123456 |
| 9 | Control Suffix | 1 letter | Series category letter restricted to A, B, C or D | A |
NINO Validation Rules (HMRC / DWP)
NINO verification enforces strict rules on allowed character combinations and reserved prefixes:
Regex: ^[A-CEGHJ-PR-TW-Z][A-CEGHJ-NPR-TW-Z][0-9]{6}[A-D]$
- 1. Verify total length is strictly 9 alphanumeric characters.
- 2. Ensure the 1st letter is not D, F, I, Q, U, V or O.
- 3. Ensure the 2nd letter is not D, F, I, Q, U, V or O.
- 4. Check that the prefix is not in the DWP reserved list (BG, GB, KN, NK, NT, TN, ZZ).
- 5. Validate positions 3 to 8 comprise 6 digits.
- 6. Ensure the final suffix is strictly A, B, C, or D.