How to find your ABN

1. Use the official ABN Lookup (free)

The Australian Business Register’s ABN Lookup is public and free, and you don’t need to log in. Search by:

• Your name — for sole traders, the ABN is registered under your personal name.
• Business or trading name — if you registered a business name.
• ABN or ACN — to check that a number is active.

The result shows the ABN, its status (active or cancelled), the registration date and whether it’s registered for GST.

2. Check your documents

• The email or letter you received when your ABN was issued
• Invoices you sent to clients
• Letters from the ATO and business activity statements (BAS)
• Your accounting or invoicing software settings
• Your business bank account details

3. Contact the ATO

If you can’t find it, contact the ATO or the Australian Business Register. You will need to verify your identity, so have your TFN and personal details ready. A registered tax agent can also find it for you.

Things to know

• Your ABN doesn’t change if you stop and restart the same business as a sole trader — it may just need to be reactivated.
• If your ABN was cancelled because you stopped trading, you can reapply when you start again.
• Finding your ABN is always free. Be wary of anyone charging you just to look it up.