UK NINO Generator & Validator
Generate a safe UK National Insurance Number for testing, or validate any NINO against the official format and prefix rules.
Generate
Uses the reserved TN prefix, which is administrative and never issued to a real person — safe for testing.
Validate
Enter a value above to validate it instantly.
A UK NINO has the form AA 99 99 99 A: two prefix letters, six digits and a suffix A–D. The generator uses the reserved TN prefix, which is administrative and never issued to a real person, so generated numbers are safe placeholders. The validator checks the shape and the prefix rules that HMRC enforces (disallowed letters and prefix combinations).
Use it to populate test data for UK systems without using a real person's National Insurance Number.
Frequently asked questions
Why does the generated NINO start with TN?+
TN is a reserved administrative prefix that is never issued to a real person, which makes generated numbers safe for testing.