How to Check My ABN: A Simple Guide for Businesses and Sole Traders

How to check your ABN: a simple guide for businesses and sole traders

If you operate a business or work as a sole trader in Australia, your Australian Business Number (ABN) is an important identifier used for tax and business purposes.

This guide explains how to check an ABN, confirm its status, and what to do if details are missing or incorrect.

Why checking your ABN matters

Checking your ABN helps ensure:

  • your business details are current and accurate
  • your ABN is active
  • you are issuing valid invoices
  • suppliers and clients can verify your business

An inactive or incorrect ABN can cause administrative and tax‑related issues.

How to check an ABN online

The official way to check an ABN is through the Australian Business Register (ABR).

You can search using:

  • the ABN number, or
  • the legal or trading name of the business

The ABN Lookup service will show whether the ABN is active, cancelled, or inactive, along with basic business details.


ABN Lookup – Australian Business Register

What to do if your ABN is inactive or cancelled

If an ABN is inactive or cancelled but the business is still operating, action may be required.

Depending on the situation, this may involve:

  • updating details on the ABR
  • re‑applying for an ABN
  • checking that business activity is correctly reported

ABN details should be kept up to date, including changes to address, structure, or business activity.

Checking other businesses’ ABNs

Businesses may also check the ABNs of suppliers or contractors, particularly when details appear inconsistent or unclear.

If an ABN provided does not match the supplier’s details, additional withholding obligations may apply.

If you can’t find your ABN

If you are unable to locate your ABN using ABN Lookup, it may also appear on:

  • previous tax returns or BAS
  • ATO correspondence
  • business registration documents

In some cases, access through your myGov or ATO business portal may be required.

Getting help with business details

If you are unsure about your ABN status or business registrations, professional advice can help ensure details are correct and compliant.

For business accounting and registration support, see:


Business accounting and advisory services