As an individual you get one ABN, and it covers every business activity you run as a sole trader. Two cafes, a consulting practice and a market stall can all sit under the same number. A second ABN is not something you apply for because you started a second business: it belongs to a second entity, such as a company, a trust or a partnership.
One ABN, as many activities as you like
An ABN is issued to an entity, not to a business. You, as an individual sole trader, are one entity however many things you do.
So the mowing round you started in March and the bookkeeping you picked up in July run under the same ABN. You report both in the same tax return, under the same number, and the ABN does not care that they are unrelated.
What people usually want when they ask this question is separation: different names, different invoices, different branding. You can have all of that without a second ABN:
- Register a business name with ASIC and attach it to the ABN you already hold. You can hold several against one ABN.
- Add or change your business activity on the ABR record so it reflects what you actually do now.
- Invoice under either name, quoting the same ABN on both.
Can a sole trader have two ABNs?
No, not at the same time and not as a sole trader. Entitlement runs to the entity, not to the business: you are entitled to an ABN if you are carrying on or starting an enterprise in Australia, and as an individual you are one entity no matter how many enterprises you run.
Applying again is also not a neutral act. The ABR runs entitlement reviews, and reapplying after an ABN has been refused or cancelled is one of the things that can trigger one.
Where people end up with two is almost always history rather than intent: an ABN from a business years ago that was never cancelled, plus a new one obtained after forgetting the first existed. That is worth cleaning up. See below.
When you genuinely do get a second ABN
A second number follows a second legal entity. Setting one up is a real decision with cost, paperwork and tax consequences, and it is not something to do for the sake of tidier invoices.
| Entity | Its own ABN? | What that means |
|---|---|---|
| You, as a sole trader | One, shared across everything you do | No separation between you and the business, legally or for tax |
| A company you set up | Yes, its own ABN and an ACN | A separate legal person. It lodges its own return |
| A partnership | Yes, its own ABN | Separate from each partner's individual ABN |
| A trust | Yes, its own ABN | Issued to the trust, not to the trustee personally |
If you are weighing up a company for the second venture, the difference between the two numbers involved is covered in ABN vs ACN.
If you already have two
It happens, usually through an old business that was never closed off properly. Leaving both open is untidy in a way that costs you: an ABN you have forgotten about still carries lodgement obligations, and the ABR runs a cancellation program that closes ABNs it is confident are no longer being used. An ABN can be picked up by it where you have not reported business income, where lodgements are not up to date, where you have told the ATO you stopped business in your latest return, or where you have lodged a final return.
There is also a rule worth knowing if you are tempted to leave a dead number sitting there: it is an offence to use an ABN after it has been cancelled, or to quote one that is not yours.
- Find out what you actually hold. Search your name on ABN Lookup, or use our find my ABN page.
- Check the status of each. One may already be cancelled, which makes the decision for you.
- Bring the lodgements up to date on the one you are closing. Cancelling does not clear what is outstanding.
- Cancel the one you are not using, dating it from when that activity genuinely stopped.
The order matters. Cancelling first and lodging later is the version that generates letters.
The one to keep
Usually the older one, if it is still active and its details are current. The number itself carries no advantage, but continuity is easier to explain than a gap, and clients and suppliers may already hold it. If the older ABN has been cancelled and the newer one is live, keep the live one and leave the cancelled record alone.
Common questions
Can you have more than one ABN?
Not as the same entity. An ABN is issued per entity, so as an individual sole trader you hold one, no matter how many businesses you run under it. A second ABN belongs to a separate entity such as a company, partnership or trust.
Can a sole trader have two ABNs?
No. You are one entity, so you are entitled to one ABN. If you apply again you should receive the number you already hold rather than a new one. People who end up with two usually have an old ABN that was never cancelled.
I run two unrelated businesses. Do I need two ABNs?
No. One ABN covers both. If you want them to look separate to customers, register a business name with ASIC against the ABN you already hold, and invoice under whichever name applies.
Do I need a new ABN if I change what my business does?
No. Update the business activity on your existing ABR record instead. You need a new ABN when the entity changes, for example a sole trader moving to a company, not when the work changes.
How do I find out if I already have an ABN?
Search your own name on ABN Lookup, check myGov if the ABN was linked to it, or use our free checker on the find my ABN page. It reports whether a number is active or cancelled, and whether it is registered for GST.
What happens if I leave an old ABN open?
It keeps its obligations. Activity statements can still be expected, and the ABR runs a cancellation program that closes ABNs it is confident are no longer in use, which can pick yours up where you have not reported business income or your lodgements are behind. Cancelling it deliberately is cleaner, and free to do yourself at the ABR.
Not sure what you already hold? Check it free.
Our ABN checker reports whether a number is active, cancelled or registered for GST. Free help on 1800 546 526.