TFN, ABN, and ACN Explained: Tax and Business Numbers in Australia
If you're working or doing business in Australia, you'll encounter three key numbers: the TFN (Tax File Number), ABN (Australian Business Number), and ACN (Australian Company Number). Your TFN is personal — it's your unique identifier for tax, superannuation, and government benefits. An ABN identifies your business for GST and invoicing purposes. An ACN is your company registration number. Understanding which numbers you need and when to get them is essential for anyone on an Australian visa with work rights.
TFN: Tax File Number
What Is a TFN?
A Tax File Number is a unique 9-digit number issued by the Australian Taxation Office (ATO). It's your personal tax identifier and stays with you for life — even if you leave Australia and return years later.
You need a TFN to:
- Work as an employee in Australia
- Lodge tax returns
- Receive government payments (Centrelink, family assistance)
- Open interest-earning bank accounts (without a TFN, the bank withholds tax at the highest rate)
- Apply for an Australian Business Number
- Manage your superannuation
Who Needs a TFN?
Anyone who earns income in Australia needs a TFN. This includes:
- Permanent residents and citizens
- Temporary visa holders with work rights (check VEVO to confirm)
- Working holiday makers (subclass 417/462)
- Student visa holders working part-time
- Partner visa holders
- Anyone receiving government payments
How to Get a TFN
For visa holders arriving in Australia:
- Apply online through the ATO website (ato.gov.au) after arriving
- You'll need your passport, visa details, and an Australian address
- Processing typically takes 28 days by post
- You can also apply in person at an ATO office or a Tax Help centre
The 28-day rule: When you start a new job, your employer will ask you to complete a Tax File Number Declaration form. You have 28 days from your start date to provide your TFN. If you don't, your employer is required to withhold tax at the highest marginal rate (currently 47%) — that's a lot more than you'd normally pay. You can get the excess back when you lodge your tax return, but it ties up your money in the meantime.
TFN tip: Apply for your TFN as soon as you arrive in Australia, even before you have a job lined up. The processing time means you'll want it ready when you need it.
TFN and Superannuation
Your TFN is linked to your superannuation (retirement savings) accounts. Australian employers must pay super contributions for employees earning $450+ per month, regardless of visa status. When you start a new job, provide your TFN to your super fund to avoid lost contributions.
Leaving Australia permanently? Temporary visa holders can claim their superannuation through the Departing Australia Superannuation Payment (DASP) scheme after their visa expires or is cancelled. You'll need your TFN to process this claim.
ABN: Australian Business Number
What Is an ABN?
An Australian Business Number is an 11-digit number that identifies your business to the government and the community. It's issued by the Australian Business Register (ABR), which is managed by the ATO.
An ABN is used for:
- Issuing invoices and receiving payments for business activities
- Registering for GST (Goods and Services Tax)
- Claiming GST credits
- Dealing with other businesses and government agencies
- PAYG withholding (if you have employees)
- Business tax returns
Who Needs an ABN?
You need an ABN if you're:
- Running a business as a sole trader
- Operating as an independent contractor (e.g., freelancing, consulting, gig work)
- Running a partnership, trust, or company
- Required to register for GST (mandatory if annual turnover exceeds $75,000)
You don't need an ABN if you're:
- Working as a regular employee (your employer handles everything)
- Not carrying on a business (occasional one-off jobs don't count)
- Doing volunteer work
The Contractor vs Employee Distinction
This is a common trap for visa holders. Some employers try to classify workers as "contractors" to avoid paying superannuation, leave entitlements, and workers' compensation. If someone tells you to "get an ABN" for what's essentially a regular employment relationship, that's a red flag.
Genuine contractor indicators:
- You control how and when the work is done
- You supply your own tools and equipment
- You can subcontract the work to others
- You bear the financial risk of the work
- You invoice for completed work
Employee indicators (even if you have an ABN):
- The business controls how you work
- You work set hours at the business's location
- You use the business's tools
- You're paid regularly (weekly, fortnightly) rather than per job
- You can't subcontract
If you're being treated as an employee but paid as a contractor, you're missing out on entitlements and may be underpaying tax. The ATO takes this seriously.
How to Get an ABN
- Go to abr.gov.au
- You'll need your TFN, identity documents, and details about your business activity
- Applications are processed immediately in most cases — you'll get your ABN on the spot
- It's free to apply
Visa holders and ABNs: You can get an ABN on most work-eligible visas, but your visa conditions still apply. A student visa holder with an ABN still can't work more than 48 hours per fortnight during study periods. The ABN doesn't change your visa conditions — check VEVO for your specific restrictions.
ACN: Australian Company Number
What Is an ACN?
An Australian Company Number is a unique 9-digit number issued by ASIC (Australian Securities and Investments Commission) when a company is registered. It's the company's legal identifier.
An ACN is required for:
- All companies registered under the Corporations Act 2001
- Proprietary limited companies (Pty Ltd)
- Public companies
- Foreign companies registered in Australia
Who Needs an ACN?
You need an ACN if you're registering a company — a separate legal entity from yourself. This is different from operating as a sole trader (which only needs an ABN).
When to register a company (and get an ACN):
- You want limited liability protection (the company's debts aren't personally yours)
- You're setting up a business structure for tax planning
- You have business partners and want a formal corporate structure
- Your business activities require a corporate entity
ACN vs ABN
| Feature | ACN | ABN |
|---|---|---|
| Issued by | ASIC | ATO/ABR |
| Digits | 9 | 11 |
| Who needs it | Registered companies only | Any business entity |
| Cost | Registration fee to ASIC | Free |
| Purpose | Company identification | Business identification for tax and GST |
| Required for | Legal obligations, ASIC compliance | Invoicing, GST, government dealings |
Here's the connection: A registered company will have both an ACN and an ABN. The ABN for a company is actually derived from the ACN (the ACN plus two leading digits). Sole traders and partnerships have ABNs but not ACNs.
How to Get an ACN
- Register your company through ASIC at asic.gov.au (or through a registered agent)
- You'll need to choose a company name, appoint directors, and provide a registered office address
- Registration costs around $576 for a standard proprietary company (fee subject to change)
- You'll receive your ACN upon registration
- Annual review fees apply to keep the company registered
For visa holders: Setting up a company in Australia on a temporary visa is possible, but it doesn't grant you any additional work rights or visa entitlements. If you're on a student visa or visitor visa, registering a company doesn't mean you can work beyond your visa conditions. For business visa holders or those looking at employer sponsorship, the company structure may be relevant to your sponsorship obligations.
Quick Reference: Which Number Do You Need?
| Situation | TFN | ABN | ACN |
|---|---|---|---|
| Starting a job as an employee | Yes | No | No |
| Freelancing or contracting | Yes | Yes | No |
| Starting a sole trader business | Yes | Yes | No |
| Registering a Pty Ltd company | Yes (personal) | Yes (company) | Yes |
| Opening a bank account | Yes | No | No |
| Lodging a tax return | Yes | If business income | No |
| Applying for government benefits | Yes | No | No |
Frequently Asked Questions
Can I get a TFN before arriving in Australia?
No. You need to be in Australia with a valid visa to apply for a TFN. Apply as soon as you arrive to avoid delays.
What happens if I don't give my employer my TFN within 28 days?
Your employer must withhold tax at the highest marginal rate. You'll get the over-withheld amount back when you lodge your tax return, but it could mean months of reduced take-home pay.
Do I need a TFN for each job?
No. Your TFN is for life. You give the same TFN to every employer, super fund, bank, and government agency.
Can I use my ABN to avoid paying tax?
No. Having an ABN doesn't reduce your tax obligations — it changes how you report and pay tax. You'll still need to lodge business activity statements (BAS) and pay income tax on your business profits. The ATO actively audits ABN holders.
I'm a migration agent — do I need an ABN?
If you're operating as a sole practitioner (not employed by a firm), yes. You'd register as a sole trader with an ABN to invoice clients and manage your business tax obligations.
Do I keep my TFN if I leave Australia?
Yes. Your TFN stays active permanently. If you return to Australia in the future, you use the same TFN. You'll also need it to claim your DASP (departing superannuation payment) after leaving.
