When you first start earning money, signing up for study, or even volunteering in more official capacities, you’ll quickly notice there’s a whole bunch of numbers you need to know—things like your TFN, ABN, Medicare number, and more.
They might not be exciting, but they’re seriously important when it comes to things like getting paid, doing your taxes, or accessing services.
Here’s a guide to the essential numbers every young Aussie needs to know—and why they matter (yes, even if you’re just starting out in part-time work or volunteering in your surf club).
1. Tax File Number (TFN)
What it is:
A TFN is your personal reference number for the Australian tax system. It’s unique to you and stays with you for life—even if you change jobs, move interstate, or stop working for a while.
Why you need it:
- So your employer can withhold the correct amount of tax from your pay
- To lodge your tax return
- To avoid being taxed at the highest rate (yep, they’ll hit you with more tax if you don’t provide one)
- To manage your superannuation accounts
How to get it:
You can apply for a TFN online through the Australian Taxation Office (ATO) website or at Australia Post. You’ll need ID, like your passport or birth certificate.
Lifesaver tip:
If you’re working as a paid lifeguard, club admin, or training assistant—your employer will need your TFN. Have it ready when you start.
2. Australian Business Number (ABN)
What it is:
An ABN is a unique 11-digit number that identifies your business to the government and community. You only need an ABN if you’re operating as a sole trader, freelancer, or running your own business (even part-time or as a side hustle).
Why you might need one:
- If you’re doing freelance work or invoicing someone directly (e.g. tutoring, graphic design, surf coaching)
- If you’re earning money outside a typical employee role
- Some casual gigs may ask you to invoice them as a contractor (just be careful you’re not being incorrectly classified—more on that below)
How to get it:
Apply through the Australian Business Register (ABR) website. It’s free, and usually only takes about 15 minutes.
Important:
If you’re being paid regularly by one employer and they’re asking you to get an ABN instead of hiring you as a casual employee—this can be a red flag. You might be entitled to benefits like super or leave, and they could be avoiding paying those. When in doubt, check with Fair Work.
3. Medicare Number
What it is:
This one’s easy—it’s the number on your green Medicare card that gives you access to Australia’s public health system.
Why you need it:
- To claim bulk-billed doctor appointments
- To fill prescriptions at discounted rates
- To access free or subsidised hospital services
When to get your own:
If you’ve turned 15, you can apply for your own Medicare card—even if you’ve always been on your parents’. It’s great for independence and makes medical appointments easier.
Lifesaver tip:
If you’re volunteering on patrol and get injured or need to see a doctor, having your own Medicare card means you can access care faster and without confusion.
4. Unique Student Identifier (USI)
What it is:
A USI is a reference number that links to your training and education records in Australia.
Why you need it:
- If you’re doing any nationally recognised training—like your Bronze Medallion, First Aid, or IRB Crew—you need a USI
- It helps track your completed units and certificates
- You’ll need it to enrol in TAFE or university too
How to get it:
Register for free at www.usi.gov.au. It’s quick and easy—and most surf club trainers will ask for this when you sign up for awards.
5. Centrelink Customer Reference Number (CRN)
What it is:
A CRN is the number that identifies you in Centrelink’s system, used for youth allowance, student payments, and other services.
Why you might need it:
- If you’re studying and applying for student support
- If you take a gap year and claim government benefits
- For some Medicare or MyGov services (as Centrelink, Medicare, and ATO all link through MyGov)
How to find or apply:
You’ll get one the first time you register with Centrelink. You can manage it all through your MyGov account.
Final Thoughts
TFNs, ABNs, USIs—yeah, they don’t exactly scream “fun.” But these numbers unlock serious adulting milestones: getting paid properly, managing tax, studying, accessing health care, and even growing your super.
So do your future self a favour:
- Keep these numbers safe (don’t just screenshot and forget them)
- Set up your MyGov account—it links most of these services in one place
- Don’t be afraid to ask for help if you’re confused (your club, parents, or even your local library can help)
Because in the world of real-life responsibilities, sometimes the boring stuff is the stuff that really matters.