How To Find Your ABN

Misplaced your Australian Business Number (ABN) or not sure if you’ve ever had one? You’re not alone.

Whether you’re invoicing, setting up a new website, opening a business bank account or registering for GST, your ABN sits at the centre of doing business in Australia.

The good news: finding your ABN (or confirming whether you have one) usually takes just a few minutes if you know where to look. In this guide, we’ll walk you through the quickest ways to locate your ABN, how to check its status, and what to do if it’s old, cancelled or you’ve changed structures.

We’ll also cover common mistakes that make ABNs hard to find and what to do next if you need to update your details, reactivate, or obtain a new ABN altogether.

What Is An ABN And Why It Matters For Your Business

An Australian Business Number (ABN) is an 11-digit identifier issued by the Australian Business Register (ABR) to businesses and enterprises. It helps government agencies, suppliers and customers identify your business for tax and regulatory purposes.

In practical terms, you’ll use your ABN on invoices, contracts, purchase orders, website footers and forms. If you invoice without an ABN, your customer may be legally required to withhold 47% from your payment under the no-ABN withholding rules.

Not every person needs an ABN. You need one if you’re carrying on an enterprise (for example, running a business as a sole trader, partnership, company or trust). If you’re unsure whether your activity counts as a business, it helps to get clear on what defines a business activity in Australia.

There are real pros and cons to consider when operating with an ABN. If you’re weighing this up, it’s worth reading about the advantages and disadvantages of having an ABN before you go further.

And if you’re asking “can I just keep trading without one?”, make sure you understand the risks of trying to run a business without an ABN.

Quick Ways To Find Your ABN (Step-By-Step)

There are several fast, reliable places to find your ABN. Start with these:

1) Check Where You’ve Already Listed It

• Invoices and quotes: Your accounting software templates often include your ABN by default.
• Email signatures, website footers and social profiles: Many businesses list their ABN for transparency.
• Any dealings with government: Look at ATO correspondence, business registrations or licence applications for references to your ABN.

2) Use ABN Lookup (Public Search)

Search the ABN Lookup service (the official public register operated by the ABR). You can search by:

• Business name
• ACN (if you operate a company)
• Your personal name (if you’re a sole trader and your name is the business name)

Tip: If you recently changed your business name or structure, try older names too. You can also tick the option to include cancelled ABNs to see historic records (helpful if you closed a business or changed structures).

3) Check ATO Online (Sole Traders) Or Online Services For Business

• Sole traders connected to myGov: Log in to myGov, go to ATO Online Services, and check your business profile or registration details to see your ABN and GST status.
• Companies/other entities: Use Online Services for Business (via myGovID and Relationship Authorisation Manager). The business portal will show your ABN, GST registration and other tax registrations.

4) Look Up Your Company’s ACN (Then Find The ABN)

If you have a company and know your Australian Company Number (ACN), search that number in ABN Lookup. It will display the associated ABN and whether the company is registered for GST.

5) Ask Your Accountant Or Bookkeeper

Your accountant or BAS agent will have your ABN on file for tax lodgements and registrations. If you’re stuck, they can usually retrieve it quickly.

How Do I Find An Old Or Cancelled ABN?

Maybe you traded a few years ago, paused operations, or moved from sole trader to a company and now need the old ABN for records. Here’s how to locate it:

• On ABN Lookup, tick “Include cancelled ABNs” before searching your name, business name or ACN. The search results will show the ABN, its status (cancelled), and cancellation date.
• Check historic invoices, bank statements and contracts from the period you traded - the ABN is often printed there.
• If you used accounting software, download old invoice lists or templates. Your ABN may be saved in the template header.

If you’ve found a cancelled ABN and are wondering whether it ever “expires”, it’s helpful to understand the difference between cancellation and expiry. This guide on does an ABN expire explains how ABNs can be cancelled (e.g. inactivity, change of structure) and when you may need to reactivate or apply for a new one.

How Do I Check If My ABN Is Active (And What It Tells You)?

Finding your ABN is step one; confirming it’s active and up-to-date is step two. Once you’ve located your ABN, search it on ABN Lookup to review:

• Status: Active or cancelled.
• Entity type: Sole trader, partnership, company, trust, etc.
• GST registration: Whether you’re currently registered and the effective date.
• Trading and legal names: Make sure these match what you use in the market.
• Other registrations: For example, PAYG withholding.

If you need a refresher, here’s a quick guide on how to check if an ABN is active and what each field means for your day-to-day operations.

While you’re reviewing your details, some businesses like to look at revenue signals or industry data associated with ABNs. If that’s on your radar, our outline on how businesses can check ABN income covers what’s possible, what’s not, and compliance considerations.

Common Scenarios That Make ABNs Hard To Find

If you’ve tried the steps above and still can’t find your number, one of these common situations may be the reason.

1) You Changed Business Structure

Moving from a sole trader to a company is a positive step, but it usually means a brand-new ABN because the legal entity changed. Your company will have its own ACN and a different ABN to your old sole trader ABN.

As part of a restructure, keep in mind that “names” can be confusing. Your “entity name” (legal name) isn’t the same thing as your “business name” (the trading name the public sees), and neither is the same as the ACN or ABN. If you’re unsure which name you used, this explainer on entity name vs business name and this one on business name vs company name can help you search the right details in ABN Lookup.

If you’re planning to incorporate now, and will need to obtain a new ABN in that process, it’s worth looking at your broader setup (constitution, shareholder arrangements, and registrations) alongside your company set up.

2) You Operate Multiple Brands Under One ABN

It’s common to run more than one venture under a single ABN (for example, a sole trader with two trading names). That can make it tricky to find your ABN if you search only by a particular brand name.

Try searching your personal name (for sole traders) or the legal entity name (for companies or trusts) in ABN Lookup. For strategy and compliance around this approach, see whether you can use one ABN for multiple businesses.

3) Your ABN Was Cancelled For Inactivity

The ABR can cancel ABNs that appear inactive. If that happened, you may still see the record in ABN Lookup (with a cancelled status). Depending on your circumstances, you might need to update your details and seek reactivation, or apply for a new ABN if your entity has changed.

4) You Never Had An ABN

Sometimes the honest answer is: you don’t have one yet. If your activities only recently crossed the line into “carrying on an enterprise” (for instance, you’ve moved from a hobby to taking regular paid bookings), now is the time to apply.

If you’ve tried to apply before and ran into issues, this guide on why your ABN application was unsuccessful covers common reasons and what to fix next.

Frequently Asked Questions About Finding Your ABN

Where can I find my ABN number quickly?

Search your invoices and email signature first. If that doesn’t work, use ABN Lookup by entering your business name, ACN or personal name (for sole traders). Sole traders can also view their ABN via ATO Online Services through myGov; companies and other entities can use Online Services for Business.

How do I know if I have an ABN at all?

Try searching ABN Lookup for your name or business name. If nothing appears, check any ATO or licensing letters. If you still can’t find a record, it’s likely you don’t have one yet.

I forgot my ABN - can I retrieve it without ABN Lookup?

Yes. Check previous invoices, your accounting software, government letters, or contact your accountant. Sole traders connected to myGov can view their ABN in ATO Online Services; companies can use the business portal via myGovID.

How do I find my old ABN number?

On ABN Lookup, tick “Include cancelled ABNs” and search previous trading names or your personal/legal name. You can also find it on old invoices, contracts or bank statements from that period.

How do I check if my ABN is active?

Enter your ABN into ABN Lookup and review the Status field. Our step-by-step guide to check if an ABN is active explains how to read the record and what to do if anything looks off.

Where can I find my ABN on myGov?

If you’re a sole trader, log in to myGov, open ATO Online Services and check your business registration details. For companies, you generally won’t see the company ABN through a personal myGov account - you’ll use Online Services for Business with myGovID.

Can I use the same ABN for multiple businesses?

Sometimes, yes - for example, a sole trader can operate multiple trading names under one ABN. But there are limits and considerations, especially if you change structures or scale. Here’s what to factor in with one ABN for multiple businesses.

What’s the difference between an ABN and an ACN or ARBN?

An ABN identifies a business or enterprise for tax and government purposes. An ACN identifies a company as a registered corporation. Foreign companies or certain bodies can have an ARBN - more on the difference between an ABN and ARBN if that’s relevant to you.

Is there a way to confirm I’m using the right name when I search?

Yes. Remember that your legal “entity name” can be different from your public “business name”. If you’re stuck, review the distinction between entity name vs business name and business name vs company name, then try both when searching ABN Lookup.

Next Steps If You Can’t Find Or Use Your Current ABN

If your ABN is cancelled, out of date, or you can’t find it because you’ve changed structures, here’s a simple plan:

• Confirm your current legal entity: Are you trading as a sole trader, partnership, company or trust right now?
• Search under the correct name: Use the entity name (or ACN for companies) in ABN Lookup.
• Update details: If your ABN record is active but shows old trading names, addresses or GST status, update your details through the appropriate portal.
• Reactivate or apply: If your activities qualify as a business and your ABN was cancelled for inactivity, you may be able to reactivate; if the entity has changed (e.g. you incorporated), apply for a new ABN for the new entity.
• Tidy up your public-facing info: Ensure your invoices, website, and contracts show the correct ABN and entity details.

If you’re at a growth point and thinking a company structure is now the right move (which usually involves a new ABN), it’s smart to get your foundations right - from registrations to governance (like a constitution) and co-founder arrangements. Our company set up support can help you get those details right and keep trading smoothly while you transition.

Key Takeaways

• You can usually find your ABN within minutes by checking invoices, email signatures, ATO portals or the public ABN Lookup register.
• ABN Lookup also shows key details - status, GST registration, entity type - so you can confirm your record is current and compliant.
• If you can’t find an ABN, it might be cancelled, under a different name, or you may never have had one. Consider whether you’re now carrying on an enterprise and need to apply.
• Structure changes (for example, moving from sole trader to company) typically mean a new ABN. Make sure your public information, invoices and contracts reflect the correct details.
• If you’re unsure whether you need an ABN or how to proceed, revisit what counts as a business activity and understand the pros and cons of having an ABN for your situation.
• When you’re ready to scale, consider whether it’s time to incorporate and formalise your setup - from ABN and GST registrations to governance and agreements.

If you’d like a consultation about ABNs and getting your business set up correctly, you can reach us at 1800 730 617 or team@sprintlaw.com.au for a free, no-obligations chat.