Tom Willis is an award-winning marketing leader and Co-founder of Lawpath. Tom’s journey journey includes steering several entrepreneurial projects and addressing the unique challenges faced by small businesses. As the Chief Marketing Officer at Lawpath, Tom has been pivotal in shaping the company’s marketing strategy and business growth.
The fastest way to find your ABN is to search your legal name on ABN Lookup, the free public register run by the Australian Business Register (ABR). It shows your 11-digit Australian Business Number, whether it’s active or cancelled, and whether you’re registered for GST. No login. No fee. About two minutes.
Maybe a client portal, a supplier form or your accountant just asked “what is my ABN?” and your mind went blank. Happens to everyone. Here’s what most guides miss, though: when people tell us they’ve lost their ABN, the number is rarely the real problem. More often they have two of them, and the one they find first is the wrong one.
- ABN Lookup is free and public. Search your legal name, not your trading name. A sole trader’s ABN is registered to them personally.
- Your ABN is already on your paperwork. Any tax invoice you’ve issued, your accounting software settings and your last BAS all show it.
- Companies and trusts log in differently. They use Online services for business with myID (the app formerly called myGovID), linked through RAM. Personal myGov won’t show a company’s ABN.
- A cancelled ABN still shows up. Switch off the active-only filter. If your structure hasn’t changed, reapplying in most cases brings back the same number.
- No ABN on an invoice costs you 47%. Business customers must withhold tax at that rate from payments over $75 (excluding GST) when you don’t quote one.
How do I find my ABN? Six places to look
Work down this list in order. Most people are done by step two.
1. Search ABN Lookup by your legal name
Open ABN Lookup, choose a name search and type the name your ABN is actually registered under. For a sole trader, that’s your full legal name as the ATO holds it. Not the name painted on your van.
The result shows your ABN, its status, your entity type, your GST registration and any business names attached to it. Share a name with half of Brisbane? Use the state and postcode shown against each result to pick out yours.
Running a company? Search the company name or your ACN instead. A company’s ABN is built from its nine-digit ACN with two check digits added to the front, so if your ACN is handy you’re most of the way there. Not sure which number is which? Here’s the difference between an ACN and an ABN.
2. Check documents you’ve already sent
Your ABN has to appear on every tax invoice you issue, so an old invoice is the quickest offline source. Other reliable spots:
- Accounting software settings. In Xero, MYOB or QuickBooks, your ABN lives in the organisation or business settings and prints on every invoice template.
- Your BAS and income tax return. Activity statements show the ABN up top, and a sole trader’s return carries it in the business schedule.
- Your ABR confirmation email. Search your inbox for “Australian Business Register. Check spam and any old email addresses too.
- Your business name registration. ASIC records each registered business name against the ABN that holds it.
- Email signatures, website footers and signed contracts. If you added it once for credibility, it’s still sitting there.
3. Log in to myGov (sole traders)
Sole traders with the ATO linked to myGov can sign in, open the ATO service and check their business details. Your ABN, GST status and registration dates are all listed. This is the best route when ABN Lookup returns a page of people with your name.
Haven’t linked the ATO to myGov yet? You’ll need to answer questions using details the ATO already holds about you, such as information from a past notice of assessment. Set aside ten minutes.
4. Use Online services for business (companies, partnerships and trusts)
Your personal myGov account won’t show a company’s ABN. Companies, partnerships and trusts use Online services for business, which you log in to with myID. That’s the Digital ID app that was called myGovID until November 2024, and plenty of guides still use the old name.
There’s a catch. Before anyone can use the portal, the principal authority (a director, for example) has to link their myID to the business’s ABN in Relationship Authorisation Manager (RAM). Yes, you need the ABN to set up the tool you were hoping would show you the ABN. If you’re stuck in that loop, get the number from step one or two, then set up RAM.
5. Ask your accountant or BAS agent
Your tax or BAS agent has your ABN on file because they lodge against it. One email and you’ll have it the same day. Ask them one extra question while you’re there: is there a second ABN in your name? That answer matters more than you’d think, and we’ll get to why below.
6. Call the Australian Business Register
Nothing above working? Phone the ABR. Expect security questions before they confirm anything, so have your TFN, date of birth and address ready. It’s the slowest route. It’s also the one that settles, once and for all, whether an ABN exists in your name.
Where to find your ABN, by business structure
| Structure | Search ABN Lookup by | Log in to | Fastest paperwork |
|---|---|---|---|
| Sole trader | Your full legal name | myGov (ATO service) | Any invoice, or the business schedule in your tax return |
| Partnership | Partnership name or a partner’s name | Online services for business (myID + RAM) | Partnership tax return or invoices |
| Company | Company name or ACN | Online services for business (myID + RAM) | Invoices, or the ACN on your ASIC records |
| Trust | Trust name or trustee name | Online services for business (myID + RAM) | Trust tax return or invoices |
Start your ABN application in minutes!
Why can’t I find my ABN on ABN Lookup?
Five reasons cover almost every “it’s just not there” moment.
- You searched your trading name. A business name only appears against an ABN if it’s registered with ASIC. An unregistered trading name won’t show up at all, so search your legal name instead.
- Your ABN was cancelled. If the search is limited to active ABNs, cancelled records stay hidden. Clear that filter and they appear with their cancellation date.
- It was never issued. An application that’s refused or sent for review produces a refusal or reference number, not an ABN. Dig through your email (spam included) for anything from the ABR.
- You changed structure. Going from sole trader to company creates a brand new ABN. Search the company name while invoicing under your old sole trader number, and the two records won’t match.
- It’s brand new. An activated ABN shows on ABN Lookup the same day. If yours still hasn’t appeared after that, use the contact form on the ABR’s website so they can correct the public record.
Do I even have an ABN?
Plenty of people searching “find my ABN” have never had one. They’ve done some freelance work, maybe a few weekend markets, and assumed it got set up along the way. It didn’t.
Three quick checks settle it. Did you ever fill in an ABN application, or have someone do it for you? Have you ever quoted 11 digits on an invoice? Does your last tax return have a business schedule? Three nos plus a blank ABN Lookup search means you don’t have one.
Do you need one? Not everyone does. An ABN is for people carrying on an enterprise, not hobbyists or employees. But if you invoice businesses, going without gets expensive. Under the no-ABN withholding rules, a business paying you more than $75 (excluding GST) without an ABN quoted must withhold 47% and send it to the ATO.
You’ll also need an ABN to register for GST or to register a business name. Straightforward applications are approved on the spot, so this is a quick fix once you decide to do it.
What we see in Lawpath consultations: it’s usually the wrong ABN, not a lost one
Across Lawpath’s accounting and legal consultations, “I can’t find my ABN” rarely means the number is gone. More often the business owner has two ABNs and is using the wrong one. These are the patterns our advisors run into again and again.
The old sole trader ABN is still active
You incorporated, started trading through the company and assumed your sole trader ABN quietly disappeared. It didn’t. ABNs don’t cancel themselves when you change structure. While the old one stays active, the ATO can keep expecting activity statements and PAYG instalments against it.
Our accountants regularly help clients vary those leftover instalments to nil, then cancel the old ABN using the date the company started trading as the cancellation date. Ten minutes of admin, and the ATO letters stop.
Paperwork attached to the wrong entity
This one bites harder than people expect. Our lawyers have seen tribunal claims lodged against a founder’s old sole trader ABN instead of their company. Our accountants have untangled payroll reporting set up under a personal ABN rather than the employing company’s, and business names still sitting on a sole trader record years after the switch.
Every one of these is fixable. Every one also eats time you didn’t plan to spend. Once you know both numbers, check that your accounting software, payroll, invoices, website and business names all point to the entity that actually trades. If a name needs to move, here’s how to transfer a business name to a new ABN.
Expecting a sole trader ABN to convert
Founders often ask us to turn their sole trader ABN into a company ABN. You can’t. A company is a separate legal entity, so it gets its own ABN alongside its ACN, and business assets move across through a sale or transfer agreement. Our guide on whether you need a new ABN when you switch to a company covers the full move.
Ready to make that change? You can register your company first, then move your trading names and contracts across in one go.
Applying twice
Someone applies, hears nothing and applies again. Now there’s a risk of a messy duplicate. Our advisors’ advice here never changes: check spam and any other inboxes first, then call the ABR to confirm whether a number was already issued before you lodge a second application.
My ABN was cancelled. Can I get the same number back?
Usually, yes. The ABR runs an ongoing program to cancel ABNs it’s confident are no longer being used. It looks for signs like no business income reported in your tax return or lodgments that have fallen behind. It also cancels a company’s ABN when ASIC deregisters the company.
If yours got swept up and you’re still in business, reapply. Where your structure hasn’t changed, the ABR will in most cases register you with the same ABN, so your invoicing history and client records still line up. In recent sole trader reactivations our accountants have lodged, the registration came through in about two business days.
Changed structure since? Then the new entity gets a new ABN instead. Our step-by-step guide to reactivating a cancelled ABN walks through the application, and this explainer on why ABNs get cancelled covers the triggers.
Want to stay off the cancellation list? Report any income or loss under your ABN in the business section of your tax return, even in a quiet year. Then update your ABN details within 28 days whenever your address, business activity or associates change.
Where does my ABN need to appear once I’ve found it?
Found it? Good. Now put it where it needs to be, and ignore a couple of myths while you’re at it.
- On every tax invoice. The seller’s ABN is one of the details a valid tax invoice must show. For sales of $1,000 or more, the invoice also needs the buyer’s identity or ABN. If a customer asks for a tax invoice on a sale over $82.50 (including GST), you have 28 days to provide one.
- Not necessarily on your letterhead or website. There’s no blanket rule forcing every business to print its ABN on its letterhead. Companies have separate rules about showing their name and ACN (or ABN) on public documents. Here’s more on whether you need your ABN on your website.
- Matching the entity doing the work. Quoting the wrong ABN is its own problem. The ATO says payers may need to withhold 47% if they have reasonable grounds to believe the ABN quoted belongs to another entity.
If your invoices are a patchwork of templates from different years, start clean with a tax invoice template that has the right ABN built in.
ABN, ACN or TFN: which number is which?
Half the “what is my ABN?” searches we see are really “which of my numbers is this one?” Here’s the quick version.
| Number | Digits | Issued by | Public? | What it’s for |
|---|---|---|---|---|
| ABN | 11 | Australian Business Register | Yes, anyone can search it | Invoicing, GST, dealing with other businesses and government |
| ACN | 9 | ASIC | Yes | Identifying a registered company (companies only) |
| TFN | 8 or 9 | ATO | No, keep it private | Your personal or entity tax affairs |
Never put your TFN on an invoice. If a form only asks for an ABN, that’s all it needs.
Find my ABN: frequently asked questions
How do I find my ABN for free?
Search your legal name or business name on ABN Lookup at abr.business.gov.au. It’s free, public and needs no login. You can also check old invoices, your accounting software settings or the ATO section of myGov.
What is my ABN number?
It’s the 11-digit number the Australian Business Register issued to identify your business. The first two digits are check digits. For a company, the other nine are its ACN. If you’ve lost it, ABN Lookup or any old invoice will show it.
Can I find my ABN using my TFN?
No public tool links the two, because your TFN is private. Log in to myGov and open the ATO service, where your ABN appears with your business details. Companies and trusts use Online services for business instead.
Is there a separate ABN register for Queensland or my state?
No. ABNs are federal and work anywhere in Australia, so every state uses the same ABN Lookup register. Your listing does show your state and postcode, which helps narrow the results if your name is common.
What if my ABN doesn’t appear on ABN Lookup?
Search your legal name rather than a trading name, and remove the active-only filter in case it was cancelled. A newly activated ABN appears the same day. If it still doesn’t show, contact the ABR through the form on its website so the public record can be updated.
What happens if I don’t show my ABN on my invoices?
Business customers paying you more than $75, excluding GST, must withhold 47% and send it to the ATO. You claim it back at tax time, but your cash flow takes the hit now. A GST-registered business also can’t issue a valid tax invoice without its ABN.
How do I find my old or cancelled ABN?
Search your legal name on ABN Lookup with the active-only filter switched off. Cancelled records stay on the register with their cancellation date. Invoices, contracts and bank statements from that period will show the number too.
Can anyone look up my ABN?
Yes. ABN Lookup is public, so anyone can see your ABN, entity name, status, GST registration, state and postcode. Your TFN, street address and income stay private.
Found it? Here’s what to do next
Found your ABN in the first two minutes? Nice work. Save it somewhere you’ll actually see it again: your phone notes, your password manager, the footer of your invoice template.
Didn’t find one, or found one that belongs to a structure you’ve outgrown? You’re not behind. This is one of the most common admin tangles we sort out, and fixing it takes less time than worrying about it did.
Register your ABN with Lawpath and get the right number, set up properly the first time.
