How to Find Your Tax File Number (TFN)?

Your Tax File Number (TFN) is a unique 9-digit number the ATO assigns to you for life. If you’ve misplaced yours, there are five ways to find it. The fastest takes under two minutes.

What is a Tax File Number (TFN)?

A Tax File Number (TFN) is a unique 9-digit identifier the ATO issues to individuals, companies, trusts, and partnerships for tax and superannuation purposes. The ATO uses your TFN to match income records, track super contributions, and process your tax return.

You need one to start a job, lodge a tax return, open a bank account, claim government benefits, and apply for an ABN. If you’re a sole trader, you use your personal TFN for your business. If you’re a company, trust, or partnership, the entity needs its own TFN entirely.

How do I find my Tax File Number?

There are four ways to track down your TFN. The table below shows which to try first based on your situation.

1. Log in to myGov or the ATO app

This is the fastest option. If your myGov account is linked to the ATO, you can find your TFN in about a minute.

In myGov: log in, select the ATO, go to your profile, and look for “Find my TFN” under personal details. In the ATO app: download it from the App Store or Google Play, log in using your myID credentials, and your TFN appears in your tax profile.

If your myGov account isn’t linked to the ATO yet, you’ll need to go through a verification step before it shows your TFN. The ATO’s setup guide walks you through the linking process. It takes around five minutes and needs your myID at Standard identity strength or above.

2. Check your documents

Your TFN appears on a handful of official documents you may already have. Look for:

• Your notice of assessment (NOA): the letter the ATO sends after processing your tax return. The TFN appears in the top right corner.
• ATO correspondence: any letter, statement, or email the ATO has ever sent you.
• Payment summaries or income statements: your employer provides these at the end of each financial year and they include your TFN.
• Superannuation account statements: annual statements from your super fund show your TFN.

One thing to keep in mind: if you’ve never lodged a tax return and don’t have old ATO paperwork, this method won’t help. Go straight to myGov or the ATO app instead.

3. Find it via Centrelink or Services Australia

If your myGov account is linked to Centrelink or Medicare, you can find your TFN through those services without needing to link the ATO first. Log in to myGov, open your Centrelink or Medicare profile, and look under personal details.

This is particularly useful if you set up your myGov account primarily through Centrelink and haven’t added the ATO link yet. It gets you the number straight away.

You can also call Services Australia on 136 240 to confirm your TFN over the phone if you have an established Centrelink record. Have your Customer Reference Number (CRN) ready before you call.

4. Ask your registered tax agent or accountant

If you’ve used a registered tax agent or accountant, they have access to your TFN through the ATO’s Tax Agent Portal. A quick email or call to their office can get it back to you the same day.

It’s also worth checking your email history. Most tax agents send confirmation emails or attach completed return documents that reference your TFN. Search your inbox for emails from your agent or anything with “tax return” in the subject line.

5. Call the ATO directly

If none of the above work, call the ATO on 13 28 61, Monday to Friday, 8:00 am to 6:00 pm. Have your proof of identity ready. Bring your full name, date of birth, and either your ABN or a document reference number from a previous return or ATO letter.

The ATO can confirm your TFN over the phone once they’ve verified your identity. If you request written confirmation, it can take up to 28 days to arrive. Phone is the faster route if you need the number urgently.

Why does my business need its own TFN?

This is where a lot of people get caught out, especially when they’re setting up for the first time. The short answer: it depends on your business structure.

Sole traders use their personal TFN for all business tax matters. Because a sole trader and their business are treated as the same legal entity, there’s no separate business TFN.

Companies, trusts, and partnerships are separate legal entities. Each one needs its own TFN, completely separate from the TFN of any individual involved. If you’re the director of a company and also a trustee of a discretionary trust, you can end up with three TFNs in play: your personal one, the company’s, and the trust’s.

In Lawpath accounting consultations, this regularly catches first-time business owners by surprise. The common assumption is that once you have a personal TFN, that covers everything. It doesn’t. When you register your company and apply for an ABN, the ATO issues a TFN for the company at the same time, but you need to keep track of it separately from your own.

A business TFN is needed to lodge company or trust tax returns, pay PAYG withholding to the ATO, open a business bank account, deal with government agencies, and receive investment income without triggering top-rate withholding tax.

What happens if you don’t provide your TFN?

This is the bit most articles skip over. You’re not legally required to give your TFN to every organisation that asks for it. But there are real tax consequences if you withhold it from the wrong ones.

If you don’t quote your TFN to a bank or investment body, they are required to withhold tax from your interest and investment income at the top marginal rate (currently 47%). That’s not a fine. It’s just tax withheld at the worst possible rate, and you’d need to claim it back when you lodge your return. Most people find that out when they spot a large unexplained deduction on a bank statement.

The same applies to super. If your fund doesn’t have your TFN on file, contributions made on your behalf can’t be accepted as concessional contributions and will be taxed at the top rate. You can add your TFN to your fund at any time and the fund will refund the excess tax, though it takes time to process.

When you start a new job, your employer gives you a Tax File Number Declaration form to complete. You’re not required to fill it in, but if you don’t, your employer must withhold tax at the highest rate. After 28 days without a TFN, they apply the ATO’s no-TFN withholding rate for the rest of the financial year.

What should I do if my TFN has been stolen or misused?

Act straight away. Someone using your TFN can lodge fraudulent tax returns, redirect your refund, or access government benefit systems in your name. The longer it goes unreported, the harder it is to untangle.

Call the ATO’s Client Identity Support Centre on 1800 467 033, Monday to Friday, 8:00 am to 6:00 pm. They can place security flags on your account, monitor for suspicious activity, and guide you through re-establishing your identity with the ATO.

Signs your TFN may have been misused include: an unexpected tax refund or debt appearing in your ATO account, a tax return lodged that you didn’t submit, or ATO letters about income or employers you don’t recognise. None of these are things to wait on.

How do I keep my TFN safe?

Your TFN is one of a small number of identifiers that, in the wrong hands, can be used for tax fraud and identity theft. Keep it accessible to you and off-limits to everyone else.

• Use a password manager. Apps like 1Password or Bitwarden are far more secure than a phone note. If you use a notes app, make sure your device has a strong PIN and screen lock enabled.
• Know who can legitimately ask for it. Employers, banks, super funds, government agencies, and registered tax agents can ask. Real estate agents, online marketplaces, and social platforms cannot. Asking for it is often a scam signal.
• Shred documents before disposal. A notice of assessment in a recycling bin is a real risk.
• Never email your TFN unencrypted. If an employer or tax agent needs it sent electronically, ask whether they have a secure portal.

How do I apply for a TFN if I don’t have one?

Applying for a TFN is free. The method depends on your situation:

• Australian citizens with a passport (15+): apply online via the ATO in about 10 minutes.
• Australian residents without a passport: apply in person at a participating Australia Post outlet with two forms of ID.
• Foreign passport holders, permanent migrants, and temporary visitors: apply online or in person with a valid passport or travel document.
• People living outside Australia: for non-residents with Australian-sourced income, apply via a paper form from the ATO.

If you’re starting a business and need an ABN as well, Lawpath can handle both. You can register your ABN through Lawpath in a few minutes. The ATO issues a company TFN as part of the business registration process.

Frequently asked questions

Key takeaways

Finding your TFN is quicker than most people expect. The myGov and ATO app routes get it done in under two minutes once your account is set up. The bigger thing to keep in mind, especially if you’re running a business, is that your personal TFN and your entity’s TFN are completely separate. Mixing them up causes real problems at tax time.

If you’re setting up a company, trust, or partnership and want to get the tax setup right from the start (TFN, ABN, business structure and all), our accounting team can walk you through it. It’s easier to sort early than fix later.

Talk to a Lawpath accountant and get your business tax setup sorted.