IRD Number Checker (New Zealand)
Check that a IRD Number is correctly formed and that its check digit computes, before you put it on an invoice. Nothing is sent anywhere.
- Free
- No sign-up
- Nothing uploaded
- Updated for 2026
- Last reviewed October 2026
- Reviewed by the Owoode team
- NZ$ NZD
- GST 15%
- IRD number
- A4
- English
Enter a number above.
Example: 49-091-850
How the number is built and checked
An IRD number has 8 or 9 digits: a base number of 7 or 8 digits followed by one check digit. The valid range is from 10,000,000 to 200,000,000; the upper limit was raised from 150,000,000 on 10 February 2026.
To check it, drop the last digit and, if 7 digits remain, add a leading zero to make 8. Multiply the 8 digits by 3, 2, 7, 6, 5, 4, 3, 2 and add the results. If the sum divided by 11 leaves remainder 0, the check digit is 0; otherwise the check digit is 11 minus the remainder. If that gives 10, repeat with the weights 7, 4, 3, 2, 5, 2, 7, 6; a result of 10 again means the number is invalid. The number is valid when the calculated digit equals the last digit supplied.
Inland Revenue offers an IRD number validation service to software providers that matches a number against a customer's name, date of birth or incorporation, and address; it is not a public lookup.
What this does and does not tell you
This page checks arithmetic, not registration. Every IRD Number carries a check digit calculated from the digits before it, which is what catches a typo. Confirming that a business is genuinely registered means asking Inland Revenue (IRD), because only they hold the register.