Every individual and business operating in Australia needs to be identified correctly for tax purposes, and that’s where the TFN and ABN come in.
While they may seem similar, they’re not interchangeable.
One is designed for personal tax affairs, the other for business activity. Misunderstanding how they work can lead to overpaying tax, unnecessary delays, and compliance issues.
If you’re unsure which one applies to you, or whether you might need both, this article will make it clear.
So, what even is an ABN?
An Australian Business Number (ABN) is an 11-digit number that says, “Hey, I run a business.” It’s your business ID, and it’s public. Anyone can look it up to confirm you’re legit. Whether you’re a sole trader, a tradie, a freelance graphic designer, or running an online store, if you’re in business, you need one.
Without it? You might struggle to get paid, look less credible, and even miss out on certain perks like government grants or claiming GST.
Let’s say you’re invoicing a client. No ABN? If they’re a business, they might have to withhold a big chunk of your payment—up to 47%—and send it straight to the ATO. That’s nearly half your money gone before it even hits your account, and you’ll be the one chasing it back. Not ideal.
And what about a TFN?
Your Tax File Number (TFN) is kind of like your tax fingerprint. It’s 8 or 9 digits long, it’s personal, and it’s private. It follows you around from job to job, and helps the ATO know who you are and how much tax you should be paying.
Now, you don’t have to give it to your boss or your super fund, but if you don’t, things get tricky. Your employer will likely withhold tax at the highest rate, and your super contributions might not even land in your account properly. It’s basically like refusing to tell your bank your BSB number. Everything just gets more complicated than it needs to be.
Can you have one without the other?
If you want to apply for an ABN, you need a TFN first. Think of it like needing your licence before you can register a car. So technically, you can have a TFN without an ABN, but not the other way around.
If you’re an employee and only earning wages, you don’t need an ABN. But if you’re doing business, even part-time, even once, you need to register for one.
Let’s make this simple:
Why this matters right now
Mistakes around TFNs and ABNs happen more often than you’d think. And they’re usually not intentional. Someone uses a TFN to invoice clients or gets an ABN without really needing one. Either way, it opens the door to tax issues—delayed payments, higher withholding, even penalties.
The fix is simple: understand what each number is for, figure out which one applies to your situation, and make sure you’re using it correctly. That small step now can save you a lot of stress later.
Here’s how to get it sorted
To get a TFN:
- Head to the ATO website or visit a participating Australia Post office.
- You’ll need proof of identity like your passport or birth certificate.
- It’s free. It’s easy. And you only do it once.
To get an ABN:
- Visit the Australian Business Register (ABR) site.
- Be clear about what kind of business you’re running.
- You’ll need your TFN and a few other personal and business details.
- It usually only takes a few minutes.
Also, don’t forget to keep your details updated. If you change your name, address, business type (anything), log in and update it. Otherwise, the ATO might assume something’s fishy and come knocking.
Bottom line?
If you’re working for someone else and getting paid wages, TFN is your go-to.
If you’re invoicing clients, selling products, or running a business, get an ABN and a TFN.
It’s not about being “official” for the sake of it. It’s about getting paid on time, being taken seriously, and not ending up with a tax mess you didn’t sign up for.
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