Business Tax File Number (2026): Who Needs a Separate TFN and How to Apply With Your ABN

Every Australian taxpayer has a tax file number, but "business TFN" causes real confusion. Do you need a second one when you start trading? Does the company you just registered have one? Can you give your ABN instead? This guide is for new sole traders, partners, company directors, trustees and treasurers of clubs and associations. It explains which business structures need their own TFN and which don't, how to apply for one with or without an ABN, who you should — and shouldn't — give it to, and what it costs a business when a TFN isn't quoted, with worked A$ examples.

Quick answer

Sole traders don't get a separate business TFN — they use their personal TFN for both personal and business tax. Partnerships, companies, trusts and other organisations need their own TFN, because each lodges its own tax return. Apply online at abr.gov.au — ideally in the same application as the entity's ABN — or through a registered tax agent or the paper form NAT 3799.

• Need both? Choose Apply for an ABN and request the TFN at the same time — see our ABN registration guide

• TFN only? Use Apply for a TFN for business under Applying for other registrations

• A business TFN is confidential; the ABN is public — never put a TFN on an invoice

• No TFN or ABN quoted on a business investment = 47% withheld from interest

What a tax file number is — and how it differs from an ABN

A tax file number is a unique number the ATO issues to individuals and organisations to identify their tax affairs. It's the key to the entity's tax account: returns, assessments, refunds and debts are all filed against it. You quote it when you apply for an ABN, lodge an income tax return, open investments that pay interest or dividends, and — for individuals — when starting a job.

An ABN does a different job. It's an 11-digit public identifier that the business quotes to customers, suppliers and government agencies. Anyone can look up an ABN; nobody outside the ATO and the bodies you give it to should ever see a TFN. A company or trust therefore usually holds three or four numbers at once — an ACN if it's a company, an ABN, a TFN, and perhaps a GST branch or withholding registration — and each has its own purpose. Our ABN vs ACN guide explains the public numbers; this guide is about the private one.

The rule that decides whether you need a business TFN is simple: if the business is a separate taxpayer, it needs its own TFN. If the business is just you, it doesn't.

Which structures need their own TFN?

Structure	Own TFN?	Which TFN goes on the ABN application	Tax return lodged
Sole trader	No	Your individual TFN	Your individual return with a business schedule
Partnership	Yes	The partnership's TFN	Partnership return (no tax payable by the partnership); partners report their shares
Company	Yes	The company's TFN	Company return — tax at 25% for base rate entities
Trust	Yes	The trust's TFN, applied for by the trustee	Trust return; beneficiaries or trustee taxed on net income
Club, association, other organisation	Yes	The organisation's TFN	Depends on whether its income is taxable

Sole trader

Own TFN?

No

Which TFN goes on the ABN application

Your individual TFN

Tax return lodged

Your individual return with a business schedule

Partnership

Own TFN?

Yes

Which TFN goes on the ABN application

The partnership's TFN

Tax return lodged

Partnership return (no tax payable by the partnership); partners report their shares

Company

Own TFN?

Yes

Which TFN goes on the ABN application

The company's TFN

Tax return lodged

Company return — tax at 25% for base rate entities

Trust

Own TFN?

Yes

Which TFN goes on the ABN application

The trust's TFN, applied for by the trustee

Tax return lodged

Trust return; beneficiaries or trustee taxed on net income

Club, association, other organisation

Own TFN?

Yes

Which TFN goes on the ABN application

The organisation's TFN

Tax return lodged

Depends on whether its income is taxable

Sole traders: your personal TFN does the job

If you trade in your own right, the ATO treats the business and you as one taxpayer. Your individual TFN covers both your personal and your business dealings, so you put it on your ABN application and keep using it for your annual return, where the business income and expenses go in the business schedule. There's no second TFN to apply for.

If you don't have a TFN yet — say you've arrived in Australia recently or never worked here — apply for an individual TFN first. Australian citizens aged 15 or over can apply online with a Strong Digital ID, and other residents and visa holders use the application route that matches their situation. The ATO doesn't charge for it.

What changes when you start trading isn't the TFN but what goes on it: business income added to any wages, possibly PAYG instalments in later years, and super contributions you choose to make for yourself. Our sole trader guide runs through the 2026-27 tax rates with a worked example.

Partnerships, companies and trusts need their own TFN

The moment the business is run through a separate entity, that entity needs a TFN in its own name, because it lodges its own return.

Partnerships. A partnership lodges a partnership tax return each year using the partnership's TFN. The partnership itself generally doesn't pay income tax; it reports its net income and each partner's share, and each partner then includes their share in their own return using their own TFN. So a two-person partnership involves three TFNs: one for the partnership and one for each partner.

Companies. A company is a separate legal person from its shareholders and directors. Once ASIC registers it and issues its ACN, it applies for its own ABN and TFN. It lodges a company tax return every year and pays company tax — 25% for a base rate entity, 30% otherwise. See our company tax rate guide for which rate applies. Directors don't use their personal TFNs for the company's tax.

Trusts. A trust isn't a legal person, but tax law treats it as a taxpayer, so the trustee applies for a TFN for the trust. The trustee lodges the trust's return, and beneficiaries include their distributions in their own returns. If the trustee is a company, there's a TFN for the trustee company and a separate TFN for the trust — the company's TFN covers the company's own affairs, not the trust's.

Other organisations. Clubs, associations, co-operatives and unincorporated bodies also apply for an organisation TFN. Some won't need to lodge a return if their income is exempt, but the TFN still matters when they open bank accounts and investments. Deceased estates use a separate ATO application.

How to apply for a business TFN

You have three routes, and the online one through the Australian Business Register is the fastest for most people. The online option is open to companies, partnerships, trusts and other organisations such as unincorporated companies, clubs and associations.

Applying for a business TFN

1. 1

   Get the entity in place first

   A company must be registered with ASIC (it needs its ACN). A partnership needs its partners agreed; a trust needs its deed signed and trustee appointed.

2. 2

   Decide — TFN with an ABN, or TFN only

   If the entity is carrying on an enterprise, it will want an ABN too. Choose Apply for an ABN on abr.gov.au and request the TFN in the same application.

   Our ABN registration guide
3. 3

   TFN only

   If the entity doesn't need an ABN — for example, a family trust that only holds investments — use Apply for a TFN for business under Applying for other registrations on abr.gov.au.

4. 4

   Have associates' details ready

   You'll be asked for details of the entity's associates — partners, trustees, company directors and officers, and other office bearers.

5. 5

   Or use an agent or the paper form

   A registered tax agent can apply for you, or you can lodge Tax file number – application for companies, partnerships, trusts and other organisations (NAT 3799).

Applying with the ABN is usually the best choice, because the details you enter once — the entity's name, address, associates and business activity — feed both registrations. The ABR says most businesses and organisations can apply for a TFN in their ABN application. If you're using the Business Registration Service to register a company and its ABN, check the summary page for a TFN request before submitting; if it isn't there, apply for the TFN separately on the ABR afterwards.

Get the entity's details exactly right. The name must match the ASIC register (for a company) or the trust deed (for a trust), and the associates must match who is really in charge. Mismatches are the common reason an application is delayed for manual checking.

Who you give a business TFN to

Because a TFN unlocks a taxpayer's affairs, it should only go to bodies that need it by law.

Individuals also give their TFN to employers using a TFN declaration; a business doesn't, because a business isn't an employee. If you run payroll, the TFNs your employees give you are theirs, not yours, and you must keep them secure. An employee who doesn't provide a TFN has tax withheld at 47% from their pay — our PAYG withholding guide covers the declaration process.

The cost of not quoting a TFN on business investments

The most expensive TFN mistake for a business is opening a term deposit or investment account without quoting its TFN or ABN. The ATO requires the investment body to withhold tax at the top rate from interest and similar payments if the investor hasn't quoted a TFN or ABN (or claimed an exemption) before the payment became payable — and that applies to companies too. If the number quoted doesn't match the ATO's records, the investor is treated as not having quoted.

The good news is that for investments held in a business capacity, either the TFN or the ABN will do. Withholding also doesn't apply to fully franked dividends from public companies. And withheld amounts aren't lost: the investment body won't refund them, but the business claims them as a credit in its tax return.

Worked example: a company term deposit

Harbour Joinery Pty Ltd puts A$50,000 of spare cash into a 12-month term deposit at 4.5% and forgets to quote its TFN or ABN. The interest is A$2,250.

What the missing TFN costs Harbour Joinery

1. 1

   Withholding by the bank

   47% × A$2,250 = A$1,057.50 withheld and sent to the ATO. The company receives A$1,192.50.

2. 2

   Tax the company actually owes on the interest

   At the 25% base rate entity rate: A$2,250 × 25% = A$562.50.

3. 3

   Credit in the company return

   The A$1,057.50 is claimed as a credit, so about A$495 comes back — but only after the company lodges its return, months later.

   Tip: Quoting the TFN or ABN to the bank before the interest is payable avoids the withholding entirely.

For a small business with tight cash flow, that's money tied up for no reason. It also happens with partnership and trust accounts, where the withholding can complicate how income and credits flow through to partners or beneficiaries. When you open any account in a business's name, quote the right entity's TFN or ABN at the start.

When a business needs a new TFN

TFNs stay with an entity for life, so most changes don't need a new one. Moving premises, changing the business name, adding a product line or changing directors all keep the same TFN — just update the ABR and ATO records.

A new TFN is needed when a new entity is created:

• A sole trader incorporates — the company is a new taxpayer with its own TFN and ABN, while the person keeps their individual TFN.
• A new trust is set up to run or hold the business.
• A partnership is formed or a business restructures into a partnership.

Whether a change of partners creates a new partnership for tax purposes depends on the facts, so check with your tax agent before the change. Because each structure change also means a new ABN and possibly cancelling the old one, read our guide to cancelling an ABN alongside this one.

Worked scenario: one family business, several TFNs

The Rossi family runs a bakery in Geelong. Here's how the numbers line up as the business grows.

Year one — sole trader. Marco starts the bakery on his own. He applies for an ABN using his individual TFN and lodges one individual return each year, with the bakery's profit in the business schedule. One TFN in play.

Year three — partnership. Marco's sister Lucia buys in as an equal partner. The partnership is a new taxpayer, so they apply on the ABR for a partnership ABN and request a partnership TFN in the same application, listing both partners as associates. Each year the partnership lodges its own return showing its net income and each partner's 50% share, and Marco and Lucia each report their share on their individual returns. Three TFNs: the partnership's, Marco's and Lucia's. Marco cancels his old sole trader ABN once the partnership takes over, unless he still runs another business under it.

Year six — company and family trust. On their accountant's advice, the siblings register Rossi Bakehouse Pty Ltd to run the bakery, and a family trust with a separate company as trustee to hold the building. Now there's a TFN for the trading company, one for the trustee company, and one for the trust — plus Marco's and Lucia's personal TFNs. The partnership lodges a final return and its ABN is cancelled.

The lesson: every time the Rossis created a new legal entity or taxpayer, they needed a new TFN, and every TFN came with a new return to lodge. That's worth costing before choosing a more complex structure — each extra entity adds accounting fees every year.

Protecting a business TFN

Treat the entity's TFN the way you'd treat a bank password. Keep it off invoices, quotes, websites, email signatures and supplier forms — those need the ABN. Store ATO correspondence securely, limit who in the business can see it, and make sure your tax agent's authority is current in ATO systems. If an ex-partner, ex-director or former bookkeeper had access, review who is linked to the business in Relationship Authorisation Manager and with your agent.

If you lose track of the TFN, it's printed on ATO letters and notices of assessment addressed to the entity and is visible in ATO Online services for business; your registered tax agent can also see it. Avoid any website offering to "look up" a TFN — there's no public TFN register. If you think a business TFN has been misused, contact the ATO promptly.

Business TFN checklist

0/7

• Confirm the structure: sole trader (use your own TFN) or separate entity (needs its own)
• Register the company with ASIC or sign the trust deed / partnership agreement first
• Apply for the ABN and request the TFN in the same application on abr.gov.au
• Have every associate's details ready — partners, trustees, directors, office bearers
• Quote the TFN or ABN on every business bank and investment account
• Keep the TFN off invoices and public documents
• New entity after a restructure? New TFN and ABN — and deal with the old ABN

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Common business TFN mistakes

Applying for a "business TFN" as a sole trader. You don't need one. Use your individual TFN on your ABN application.

Using a director's personal TFN for the company. The company is a separate taxpayer. Its returns, bank accounts and investments must use the company's TFN or ABN.

Mixing up the trustee's TFN and the trust's TFN. A company trustee has its own TFN for its own affairs; the trust's return uses the trust's TFN.

Forgetting to quote on new accounts. It's the quickest way to lose 47% of your interest until tax time.

Putting the TFN where the ABN belongs. Customers and suppliers only ever need your ABN. If you've sent a TFN on an invoice template, fix the template — our invoice generator has an ABN field and no TFN field for exactly this reason.

Official links

• ATO — Tax file number for businesses
• ATO — TFN application for companies and other organisations (NAT 3799)
• ABR — Applying for other registrations (Apply for a TFN for business)
• business.gov.au — Register for a tax file number
• ATO — Apply for an individual TFN
• ATO — Withholding from investment income

What to do next

Work out your structure first; the TFN follows from it. If you're a sole trader, you already have what you need — apply for your ABN with your own TFN. If you're setting up a company, register it with ASIC using our company registration guide, then apply for its ABN and TFN together. Partnerships and trusts can do the same on the ABR once the agreement or deed is signed. Then quote the right number on every account you open.

This is general information, not legal or tax advice — confirm on the official source or with a professional.

Frequently asked questions

Do I need a separate tax file number for my business?

Only if the business is a separate entity. Sole traders use their individual TFN for both personal and business tax. Partnerships, companies, trusts and other organisations — clubs, associations, unincorporated bodies — each need their own TFN, because each lodges its own tax return. Apply for it online through the Australian Business Register, ideally together with the ABN.

How do I apply for a TFN for a company, partnership or trust?

Apply online at abr.gov.au. If you also need an ABN, choose Apply for an ABN and request the TFN in the same application. If you only need the TFN, use the Apply for a TFN for business option under Applying for other registrations. You can also go through a registered tax agent or lodge the paper form NAT 3799.

Is a business TFN the same as an ABN?

No. The ABN is an 11-digit public number used on invoices and in dealings with other businesses and government. The TFN is a confidential number the ATO uses to identify the entity's tax account and returns. A company, partnership or trust usually has both; a sole trader has a business ABN but uses their personal TFN.

What happens if my company doesn't quote a TFN to its bank?

If a business doesn't quote a TFN or ABN on an investment such as a term deposit, the bank must withhold tax at the top rate — 47% — from the interest. For investments held in a business capacity you can quote either the TFN or the ABN. Amounts withheld aren't refunded by the bank; the business claims them as a credit in its tax return.

Does a sole trader need a new TFN when they become a company?

The sole trader keeps their personal TFN, but the new company is a separate legal entity and needs its own TFN, as well as its own ABN. Apply for the company's TFN when you apply for its ABN after ASIC registers it. The company then lodges its own tax return each year.

How do I find my business TFN if I've lost it?

Check ATO letters and notices of assessment addressed to the business, look in ATO Online services for business, or ask your registered tax agent, who can see it in their client records. Never search for it on public websites — unlike the ABN, a TFN isn't published anywhere. If none of these work, contact the ATO.

Sources & verification

Figures on this page were checked against the sources below when it was last reviewed on 11 October 2026. Each rate and limit is stored once with its own official source and review date, and official update channels are monitored daily so changes are picked up. How we verify

1. 1.Tax file number (business registrations) — Australian Taxation Office · accessed 11 October 2026
2. 2.TFN application for companies and other organisations (NAT 3799) — Australian Taxation Office · accessed 11 October 2026
3. 3.Register for a tax file number — business.gov.au · accessed 11 October 2026
4. 4.Applying for other registrations — Australian Business Register · accessed 11 October 2026
5. 5.Withholding from investment income — Australian Taxation Office · accessed 11 October 2026
6. 6.Apply for a TFN — Australian Taxation Office · accessed 11 October 2026
7. 7.ABN entitlement — Australian Business Register · accessed 11 October 2026
8. 8.Australian Company Number (ACN) — ASIC · accessed 11 October 2026