A lost tax file number is one of the easier bits of business admin to fix, because you don’t apply for a new one. You recover the number you already have. Your TFN is yours for life, so sorting out a lost tax file number means tracking it down through myGov, an old ATO document, your accountant, or a quick call to the ATO.
Here’s where the panic usually kicks in. You’ve started a new job, payroll wants your TFN by Friday, and you have no idea where it went. Take a breath. Nine times out of ten the number is sitting in a document you already have, and you can have it back in minutes.
- You don’t get a new TFN, you recover your existing one. Every person gets one TFN for life. A name change, a move overseas, or 20 years between jobs makes no difference. The number stays the same.
- The fastest fix is myGov or the ATO app. If your myGov account is linked to the ATO, your TFN sits under your personal details. About two minutes, start to finish.
- No myGov? Raid your paperwork. Your TFN is printed on old notices of assessment, income statements, payslips and super statements.
- Still stuck? Phone the ATO on 13 28 61. Have your ID ready. They’ll ask questions from your tax history before reading the number out.
- Lost is not the same as stolen. If you think someone else has your TFN, ring the ATO Client Identity Support Centre on 1800 467 033 straight away.
How do I find my lost tax file number?
Start online. The quickest way to find a lost tax file number is through your myGov account or the ATO app, and most people never need to pick up the phone. If that doesn’t work, you’ve got a paper trail, your accountant, and the ATO’s phone line as back-ups. Run through them in that order.
Check myGov or the ATO app first
Got a myGov account already linked to the ATO? You’re minutes away. Sign in, open ATO online services, then go to My profile and Personal details. Your TFN is on that screen. The ATO app shows it the same way once you’ve signed in with your myGov details. The ATO confirms this is the main online route on its lost or stolen TFN guidance.
One catch trips people up. If your myGov isn’t linked to the ATO yet, you’ll need an ATO-issued reference (like an old notice of assessment) to link it first. No ATO account at all? Skip straight to the paperwork below.
Look at documents you already have
Your TFN never changes, so any older ATO or employment document still carries the right number. Worth a hunt through these:
- Your most recent notice of assessment
- An income statement, or an old PAYG payment summary from an employer
- A superannuation member statement
- Letters from the ATO, such as a statement of account
Found one? You’re done. A TFN printed on a five-year-old notice is just as valid as one issued yesterday, because it’s the same number it always was.
Ask your accountant or tax agent
If a registered tax agent lodged your last return, they keep your TFN on file and can read it back after a couple of identity questions. Most people forget this one. It’s often faster than sitting in the ATO’s phone queue, especially for small business owners who already work with an accountant.
Call the ATO
Out of options online and on paper? Phone the ATO’s individual enquiries line on 13 28 61, 8am to 6pm Monday to Friday. There’s also a self-help line on 13 28 65 for requesting your existing TFN.
Before you dial, get your ID together: full name, date of birth, address, and details from a past return or super account. This is where people come unstuck. If you can’t answer the verification questions, the operator can’t release your TFN over the phone, and you’ll be pushed down the slower form route instead. Gather everything first.
What if I’ve never had a TFN, or genuinely can’t find it?
Turned the house upside down and still can’t find your lost tax file number? Or never had one to begin with? There’s a formal path for that. You complete the ATO’s TFN application or enquiry form for individuals (the NAT 1432) and provide certified copies of original ID, like a passport or birth certificate.
The ATO then posts your TFN, or drops it into your myGov inbox, which can take up to 28 days. It’s the slow lane. But it’s the secure fallback when every quicker option has dried up.
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Can I get a new tax file number if I’ve lost mine?
No. This question comes up constantly, so it’s worth being blunt about: you can’t get a new TFN just because you’ve misplaced the old one. You’re issued one TFN for life. Change your name, move interstate, leave the country and come back a decade later, and the number follows you the whole way.
The ATO simply updates your details against the same TFN. So the job is always to recover a lost tax file number, never to replace it. The one exception is a stolen TFN, where the ATO adds protections to your existing number rather than handing you a fresh one. More on that next.
What if your TFN has been stolen, not just lost?
A lost TFN and a stolen TFN are two very different problems. Lost means you’ve misplaced the number. Stolen means someone else has it and could lodge a fake return, redirect your refund, or open accounts in your name. If you suspect the second one, act today, not next week.
Phone the ATO Client Identity Support Centre on 1800 467 033, 8am to 6pm Monday to Friday. That’s a different number from the general enquiries line, and it connects you to a team that handles identity theft specifically. The ATO sets out what happens next on its help for identity theft guidance. They’ll flag your account, watch for suspicious activity, and walk you through re-establishing your identity.
Here’s the part most articles skip. Once your TFN is flagged as compromised, the extra security tends to stay on your account for good. Every time you or your tax agent need to lodge or access your records, the ATO opens a short verification window and you confirm who you are again. It’s protective, and it’s the right call, but it adds a step to your tax life from then on. Which is exactly why guarding your TFN is worth the effort. If more of your identity has been exposed beyond just your TFN, contact IDCARE on 1800 595 160 as well.
Recovering a lost TFN for a company, trust or partnership
Read this bit carefully, because a lot of older guides get it wrong. A company, trust or partnership has its own TFN, completely separate from your personal one. When you register a company or set up a trust, that entity is issued its own TFN as part of the process. You do not recover a business TFN through your personal myGov.
This is the single most common mix-up we see when people set up an entity through Lawpath: they assume the company’s TFN and their own personal TFN are the same number. They’re not. Treating them as one number is how a “lost” business TFN turns into an afternoon of frustration.
To recover a business’s lost tax file number:
- Sign in to ATO Online services for business (the old Business Portal was retired back in 2021, so any guide telling you to use it is out of date)
- Check the entity’s past tax returns, BAS, or activity statements
- Ask the registered tax agent who looks after the business
- Dig out your original TFN registration confirmation
A registered tax agent can pull a business TFN through their agent portal, usually faster than you’ll manage on your own. And if you’re setting up a new structure now, getting the registrations right from day one saves this exact headache later. Sort out how tax works for each business structure first, then register your company with the right details in place. If you’re earlier in the journey, the basics of what an ABN is are a sensible starting point.
How to keep your TFN safe so this doesn’t happen again
Found it? Good. Now make this the last time you go hunting. Treat your TFN like your bank PIN. A few habits that actually work:
- Save it in a password manager or an encrypted file, not a note on your phone
- Keep any paper documents showing your TFN somewhere locked
- Only hand it to people who genuinely need it: your employer (after you start), your bank, your super fund, the ATO, and your tax agent
- Treat any email, text or DM “from the ATO” asking for your TFN as a scam, because the real ATO never asks that way
There’s a real cost to going without it, too. If you don’t give an employer or bank your TFN, they’re required to withhold tax at the top marginal rate of 47%, so a missing number hits your take-home pay fast. You get 28 days to give a new employer your TFN before that withholding starts. That’s your deadline to recover a lost tax file number, not a vague “sometime soon”.
Frequently asked questions
How do I find my lost tax file number without myGov?
Check old paperwork first. Your TFN is printed on past notices of assessment, income statements, payslips and super statements. If none turn up, phone the ATO on 13 28 61 with your ID ready, or ask the tax agent who lodged your last return. The only official online method is myGov, so without it your options are paper or the phone.
How long does it take to recover a lost TFN?
It depends how you find it. Through myGov, a document, or a phone call after an identity check, it’s instant. If the ATO has to verify you through the NAT 1432 form and post it out, allow up to 28 days. The fastest route is almost always myGov or an old notice of assessment.
Can I get a new TFN if I lost mine?
No. You get one TFN for life. The ATO won’t issue a new one because you misplaced it, even after a name change or years overseas. Your details are updated against the same number. The only exception is identity theft, where the ATO adds protections to your existing TFN rather than replacing it.
Can I start a new job without my TFN?
Yes, but you have 28 days to give it to your employer. Miss that window and they must withhold tax at the top rate of 47%, which cuts your pay sharply until you provide it. Recover your lost tax file number before that month is up and you’ll avoid the hit.
Is my personal TFN the same as my company’s TFN?
No. You have a personal TFN, and your company, trust or partnership has its own separate TFN, issued when the entity is set up. You recover a business TFN through ATO Online services for business or your tax agent, not your personal myGov account.
I’ve moved overseas. Is my Australian TFN still valid?
Yes. Your TFN stays with you for life, even if you leave Australia for years and come back. You don’t reapply. If you’re a foreign resident or new migrant who has never had one, you apply for a TFN online or through the ATO’s forms for people in your situation, using proof of identity.
What number do I call if my TFN has been stolen?
Phone the ATO Client Identity Support Centre on 1800 467 033, 8am to 6pm Monday to Friday. It’s separate from the general line. The team will flag your account, watch for suspicious activity, and guide you through re-establishing your identity. If wider personal information was exposed, contact IDCARE on 1800 595 160 too.
Will the ATO email or text me my TFN?
No. The ATO will never send your TFN, or ask for it, by email, text or social media. You find it through myGov, on official documents, or by phoning the ATO directly. Treat any message asking you to click a link and “confirm” your TFN as a scam.
You’ll have it back before you know it
Reading this in a mild panic before a tax deadline or a new job start date? You’re in good company. A lost tax file number is one of the most common bits of admin people lose track of, and it’s almost always quick to fix. Check myGov, dig out an old notice, or make one phone call, and the number turns up.
The bigger win is never having to do this again. If you run a business, the simplest fix is keeping your tax details, documents and ATO dealings in one place instead of scattered across drawers and inboxes. Sort your business tax and records in one place with Lawpath, and you won’t be hunting for a number at deadline time again.
