Shape, check digit, accepted and refused examples and the API call for ACN / ARBN / ABN in Australia. Every example on this page is run through the same validators as the free identifier validator, so a value shown as accepted is a value the validator accepts.
| Field | Value |
|---|---|
| Register | ASIC (ACN, ARBN) |
| Shape | N{8} C |
| Check digit | Enforced. Weights 8,7,6,5,4,3,2,1 over the first 8 digits; check = (10 - sum mod 10) mod 10. Shown in ASIC’s 3-3-3 form. |
| Worked example (accepted) | 004 028 077 |
| Normalised form | 004 028 077 |
| Also accepted as input | 004028077 · ACN 004 028 077 |
| A one-character slip | 004 028 078 is refused |
| Regex (normalised form) | ^[0-9]{3} [0-9]{3} [0-9]{3}$ |
| API call | GET /companies/search?country=AU&company_number=004 028 077 |
| VAT number | the ABN (11 digits), while active and registered for GST — published or confirmed by the register |
ACN and ARBN share one number space. An 11-digit number is an ABN, a separate number. Proprietary, public and foreign companies only.
curl "https://api.prometiam.com/functions/v1/risk-api/companies/search?country=AU&company_number=004%20028%20077" \ -H "Authorization: Bearer YOUR_API_KEY"
| Field | Value |
|---|---|
| Register | Australian Business Register |
| Shape | N{2} N{9} |
| Check digit | Enforced. 11 digits. Subtract 1 from the first digit, then weights 10,1,3,5,7,9,11,13,15,17,19; the sum must divide by 89. |
| Worked example (accepted) | 49004028077 |
| Normalised form | 49004028077 |
| Also accepted as input | 49 004 028 077 · ABN 49004028077 |
| A one-character slip | 49004028078 is refused |
| Regex (normalised form) | ^[0-9]{11}$ |
| API call | GET /companies/search?country=AU&abn=49004028077 |
| VAT number | the ABN itself, while active and registered for GST — published or confirmed by the register |
The ABN is the GST number while the business is active and registered for GST. It is searched with abn= and is never taken by company_number.
curl "https://api.prometiam.com/functions/v1/risk-api/companies/search?country=AU&abn=49004028077" \ -H "Authorization: Bearer YOUR_API_KEY"
Shape notation: N digit · L letter · X digit or letter · C check digit or character · {n} repeat n times.
A valid shape and check digit prove that a number is well-formed, not that a company holds it. Only a lookup in the register answers that.
Register data that the API serves for Australia carries this credit:
Contains data from the Australian Securities and Investments Commission (ASIC) Company Dataset and the Australian Business Register (ABN Bulk Extract), licensed CC BY 3.0 AU (creativecommons.org/licenses/by/3.0/au/). Adapted by Prometiam (joined, normalised, status derived).
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