Do you need an ABN? The law does not make one compulsory for everyone. But if you work for businesses and do not give them an ABN, they may have to hold back 47% of what they pay you.
What an ABN is
An Australian Business Number (ABN) identifies your business to the government and to the businesses you work for. It goes on your invoices and quotes.
For a sole trader, it is how a customer knows you are running a business.
Who can get an ABN
The ABR says you can get an ABN if you are running or starting a business or other enterprise in Australia. Business.gov.au puts it the same way: to get one, you need to be running a business.
- Working for yourself. A plumber, electrician, painter or landscaper taking their own jobs is running a business.
- Hobbies. Business.gov.au says you are not eligible for an ABN for a hobby.
- Employment. The ABR says that if you are engaged as an employee for an activity, you are not entitled to an ABN for it.
Where the line falls depends on the whole picture. The ABR has an online entitlement check. If you are unsure, use it, or ask an accountant.
Who needs an ABN in practice: what happens without one
This is where it can hurt cash flow. The ATO says a business paying a supplier who has not quoted an ABN generally has to withhold 47% of the payment. It sends that to the ATO.
The rule is aimed at businesses paying their suppliers. The ATO lists exceptions, such as payments of $75 or less.
Where it applies, you would be paid just over half of what you invoiced. The rest is dealt with through your tax return. Ask an accountant how that works for you.
The ATO has a Statement by a supplier form for people who are not required to quote an ABN. It says you cannot use it if you are running a business or are entitled to an ABN.
When you need one for GST
You need an ABN before you can register for GST. The ATO says you must register once your GST turnover is $75,000 or more.
The same applies if it is likely to reach that in the next 12 months. Apply within 21 days of that point. Below $75,000 you can still register by choice.
So the $75,000 figure is about GST. It is not the line for whether you can have an ABN.
How to apply
Check you are entitled with the ABR's entitlement check, then apply through the ABR. It is free.
Business.gov.au says to have your business structure, proof of identity, and details of your activities and associates ready. It also says registering through the ABR is free, so check the price before you pay anyone to do it.
If your set-up changes
Business.gov.au says you need to cancel your ABN if you move from a sole trader to a company or partnership. If a cancelled number is the problem, read how to reactivate an ABN.
Once you have it
Put your ABN on every invoice and every job quote. Then make sure your business name, phone and service area match on your website and Google profile. Our guide to local search covers that.
This is general information, not tax or legal advice. Rules change, so check the sources below or ask an accountant.
Sources
- Register for an Australian Business Number (ABN)Business.gov.au. Checked 16 October 2026.
- ABN entitlementAustralian Business Register. Checked 16 October 2026.
- Sole trader: ABN entitlementAustralian Business Register. Checked 16 October 2026.
- Difference between a business and a hobbyBusiness.gov.au. Checked 16 October 2026.
- Pay as you go (PAYG) withholdingAustralian Taxation Office. Checked 16 October 2026.
- Payments you don't withhold fromAustralian Taxation Office, exceptions to the 47% rule. Checked 16 October 2026.
- Statement by a supplier not quoting an ABNAustralian Taxation Office. Checked 16 October 2026.
- Registering for GSTAustralian Taxation Office. Checked 16 October 2026.
Once your ABN is sorted, customers check your Google profile next. That is part of our local SEO service.