Summary
- Businesses in Australia are legally required to provide their Tax File Number (TFN) for tax and superannuation purposes, and failing to do so can result in higher tax withholding rates.
- Sole traders, companies, and partnerships each have distinct TFN requirements, and using the correct TFN for the right purpose is essential for compliance.
- A TFN is permanent and unique to each entity, meaning businesses should store it securely and use it only for authorised purposes.
- This article is a plain-English guide to Tax File Numbers for Australian business owners, covering how to find, apply for, and manage a TFN under Australian tax law.
- The content has been produced by LegalVision, a commercial law firm that specialises in advising clients on business taxation and compliance matters.
Tips for Businesses
Keep your TFN stored securely and limit access to authorised personnel only. Ensure your business structure has the correct TFN registered with the Australian Taxation Office. If your structure changes, such as moving from sole trader to company, obtain a new TFN for the new entity promptly.
A Tax File Number (TFN) is your unique nine-digit identifier for all tax and superannuation matters in Australia. The Australian Taxation Office (ATO) issues it once, and you keep it for life. This article will guide you through the steps to locate your TFN and ensure it remains secure.
What is a Tax File Number (TFN)?
A Tax File Number (TFN) is a nine-digit number issued to you as a personal reference number for tax and superannuation. It is a unique number. You will also use your TFN if you are receiving government benefits, lodging an online tax return and applying for an Australian Business Number (ABN). For example, you will need it when filing a tax return. Once you have a tax file number, you have it for life, no matter what changes happen in your life. So, how do you keep track of it and find it when it has become lost?
Where Should I Look for My TFN?

If you are at home, in your office, or another place of work, the first place you can look is an income tax notice of assessment from the Australian Tax Office (ATO). You will find your TFN in the top right-hand corner of the assessment. Other documents that should display your TFN include payslips and superannuation statements. However, these are not always readily available. If you do not have a TFN, you will need to fill out a tax file number application.
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Finding Your TFN Online
MyGov is a one-stop shop for many key government services, including:
- ATO;
- Centrelink;
- Australian JobSearch;
- Medicare; and
- My Health Record.
If you run a business, you can also connect your ABN to your MyGov account to access online government services for business. Importantly, you can view your TFN through your myGov account, so once you are registered, you will have this information at your fingertips no matter where you are.
If you are a sole trader, your TFN will be used for your ABN. You do not receive another TFN for setting up an ABN.
I Have Lost My TFN
If you simply cannot remember your TFN, you can follow the tips on this page to help you find it again so you can continue using it. You can search in physical documents, look for it on myGov or simply call the ATO or visit their website to achieve this.
However, if you believe your TFN has been lost, stolen or accessed by an unauthorised third party, you should phone the ATO’s Client Identity Support Centre to help you. By calling 1800 467 033, you can access advice, further information and implementation of security measures.
Temporary Residents and TFNs
If you are arriving in Australia on a working holiday visa or temporary work visa, you are eligible to apply for a TFN. The process is similar to that for permanent residents, but there are some differences:
- You can apply for a TFN online on the ATO website.
- You will need to provide details of your valid passport and Australian visa.
- Your TFN is valid for the duration of your stay in Australia. If you leave Australia and later return, you will use the same TFN.
If you start working in Australia without a TFN, you may be subject to higher tax rates on your income.
Key Takeaways
Your TFN is an important number, and you will need it when filing a tax return. If it falls into the wrong hands, it can be used by other individuals for identity fraud. This is why you should never keep it on a piece of paper in your wallet or save it on your mobile phone. Even sending it via text message or filling out an online form is not 100% secure. The safest way to provide your TFN to an employer is by completing a TFN declaration form.
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Frequently Asked Questions
Yes, if you have a myGov account and have connected your account with the Australian Tax Office, you can locate your TFN online. Your TFN will be located inside the My Profile > Personal Details menu.
When you lodge your tax return, the Australian Tax Office will issue you a Taxation Notice of Assessment. On this form, you will find your Tax File Number. Your TFN may also be located on your ATO Payment Summary.
You can find out what your TFN is by calling the Australian Tax Office on 13 28 61 during business hours or contacting your accountant if you have one.
While a TFN is not compulsory, you need one to avoid paying more tax than necessary. A TFN also assists you with lodging tax returns. Without a TFN, tax will be deducted from your income at the maximum rate.
A trust should have its own TFN, which the trustee uses when lodging the trust’s income tax return. If the trust operates as a business, a TFN is usually issued when an ABN is registered.
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