NHS Number Generator
NHS number generator for UK healthcare testing and integration purposes.
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About NHS Numbers
The NHS Number is a unique 10-digit number used by the National Health Service in England, Wales, and the Isle of Man to uniquely identify patients.
The check digit calculation uses a weighted Módulo 11 checksum with weights from 10 to 2. A remainder result of 10 represents an invalid number according to official NHS guidelines.
Anatomy & Structure of NHS Number (10 Digits)
The National Health Service patient identifier consists of 10 numeric digits:
| Position | Field | Length | Meaning & Rule | Example |
|---|---|---|---|---|
| 1 to 9 | Patient Identifier | 9 digits | Unique sequential patient index in NHS England and Wales | 943476591 |
| 10 | Check Digit | 1 digit | Modulo 11 checksum digit (numbers resulting in 10 are discarded) | 9 |
NHS Number Validation Algorithm (Modulo 11)
The official NHS formula weights the first 9 digits from 10 down to 2:
CheckDigit = 11 - (sum(d_i * (11 - i)) % 11)
- 1. Multiply each of the first 9 digits by weights: [10, 9, 8, 7, 6, 5, 4, 3, 2].
- 2. Compute the total sum of all products.
- 3. Compute remainder: Remainder = Sum % 11.
- 4. Compute check digit: CheckDigit = 11 - Remainder.
- 5. If CheckDigit == 11, final check digit is 0.
- 6. If CheckDigit == 10, the NHS number is INVALID by regulation and rejected.