New Zealand NHI Number Generator
Official National Health Index (NHI) generator for New Zealand healthcare following HISO 10046 Modulo 11 standard.
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About the National Health Index (NHI)
The National Health Index is the unique lifetime health identifier allocated to every individual receiving healthcare in New Zealand.
Governed by Health New Zealand (Te Whatu Ora), it underpins electronic medical records, e-prescriptions, lab tests, and hospital clinical data.
NHI Number Anatomy & Structure
The National Health Index identifier consists of exactly 7 alphanumeric characters in the AAANNNN format:
| Position | Field | Length | Meaning & Specification | Example |
|---|---|---|---|---|
| 1 to 3 | Letter Series | 3 uppercase letters | 24-letter alphabet excluding I and O (to prevent visual ambiguity with 1 and 0) | ABC |
| 4 to 6 | Numeric Base Series | 3 digits | Sequential digits representing the patient core identifier | 123 |
| 7 | Check Digit | 1 digit | Integrity check digit calculated via Modulo 11 with decreasing weights [7, 6, 5, 4, 3, 2] | 4 |
Official Algorithm (HISO 10046 Modulo 11)
Standardized by Health New Zealand (Te Whatu Ora) under HISO 10046:
Map A-Z (excluding I/O) to 1-24; Weights = [7, 6, 5, 4, 3, 2]; Rem = Sum % 11; DV = 11 - Rem (or 0 if Rem == 0).
- 1. Convert the first 3 letters into numerical values 1 to 24 (excluding letters I and O).
- 2. Multiply the first 6 characters by decreasing weights [7, 6, 5, 4, 3, 2].
- 3. Sum the products and calculate the remainder modulo 11.
- 4. If remainder is 0, check digit is 0.
- 5. Otherwise, subtract remainder from 11. If 11 - remainder equals 10, the number is rejected or normalized as per HISO 10046.