Try 51 824 753 556 (the ATO). A 9-digit ACN or part of a business name works too.

Your lookup goes from our server to the Australian Business Register. Our code doesn’t keep a record of what you look up or who asked; the register’s answer is held for 15 minutes so repeat lookups don’t bother it. A number that fails its check digit is answered here without asking the register.

Data from the Australian Business Register (ABN Lookup), as it stands when you look it up. This is Digital Greenhouse’s own free tool: it isn’t the official ABN Lookup service, and it isn’t affiliated with or endorsed by the Australian Business Register, the ATO or the Australian Government. This is general information, not legal, tax or financial advice.

Using an AI agent or a script? Call this tool as an API

AI agents and scripts can call this tool directly, to check their work or look something up, and get JSON back with the same answer this page gives. No key needed.

GET https://digitalgreenhouse.com.au/api/tools/abn-lookup?query=51824753556&state=nsw

query — string, required. An ABN (11 digits), an ACN (9 digits) or a business name. Spaces and punctuation in numbers are ignored. Also accepted as q, abn, acn, name, number.
history — boolean, default false. true = also return previous names, locations and status changes for an ABN or ACN (the register's history).
active — boolean, default true. Name searches only: true = active ABNs only (the default); false = include cancelled ABNs.
state — string, one of all | nsw | vic | qld | wa | sa | tas | act | nt, default all. Name searches only: limit matches to one state or territory by the main business location.
postcode — string, optional. Name searches only: limit matches to a 4-digit postcode.
limit — integer, default 20. Name searches only: how many matches to return (1 to 50).

The API answers from our server, and our code doesn’t store what you send. Fair-use limits apply. API guide · all endpoints (JSON) · OpenAPI

What an ABN lookup tells you

Every Australian Business Number is recorded on the Australian Business Register (ABR), kept by the Registrar of the ABR and administered by the ATO. The public part of each record shows the legal name of the business, its ABN status (active or cancelled, and since when), its entity type (sole trader, company, trust, partnership and so on), whether it’s registered for GST and from what date, the state and postcode of its main business location, and the business names it trades under, each with the date it was registered. Where they apply, the record also shows whether the entity is an endorsed deductible gift recipient (DGR), a charity registered with the ACNC, its charity type and tax concessions, and when the record was last updated. This tool asks the register for that record, using the ABR’s current web methods, and lays it out in plain English. Ask for the history and it adds previous names, previous locations and every change of ABN status.

When to check an ABN

Before you pay a new supplier. Fake invoices and “we’ve changed our bank details” emails are among the most common scams on Australian businesses. Check that the ABN is active and that the name matches who you think you’re paying. Then confirm any change of bank details by phone, on a number you already have.
When an invoice charges GST. Only a business registered for GST can charge it. If the lookup says “not registered for GST” but the invoice adds 10%, query it before you pay.
When a supplier doesn’t quote an ABN. If a business supplying you doesn’t give you an ABN, you may have to withhold tax from the payment at the top rate (currently 47%). The ATO explains when this applies, including the exceptions.
Before you register a .com.au domain. A .com.au or .net.au name usually needs an active Australian ABN or ACN (an Australian trade mark or ARBN can also qualify), and the name has to be connected to the business. The number is checked when the name is registered. Chill Domains, our .au domain service, checks an ABN or ACN against the register before you pay.

It says “not on the register”, but I’ve just got my ABN.

A brand-new ABN can take a few days to appear in ABN Lookup. Check the number against your ABN confirmation, and try again in a day or two.

Does it check the number’s maths too?

Yes. Every ABN and ACN has a built-in check digit, so a typo or a made-up number usually fails before any register is asked. An ABN is 11 digits: subtract 1 from the first digit, multiply each digit by a fixed set of weights, add them up, and a genuine ABN divides evenly by 89. An ACN is 9 digits, where the last digit is a checksum of the first eight. A number that fails is answered here straight away, with no register call. A number that passes is only well-formed, which is why this tool goes on to ask the register whether it exists, who holds it and whether it’s active. (This replaced our separate ABN / ACN validator in October 2026.)

Why can I look up an ACN here?

An ACN is the number ASIC gives a company. Most companies also have an ABN, and the register links the two, so an ACN lookup shows the company’s ABN record. A company without an ABN won’t show here; ASIC’s registers list every company.

Why can’t I see an address or phone number?

The register only makes the state and postcode of the main business location public. It doesn’t publish street addresses or contact details, so neither can we.

Can I see a business’s previous names?

Yes. After a lookup, choose “Show this ABN’s history” and the register’s earlier entity names, former business names, previous main business locations and every change of ABN status appear with their dates. Trading names are left out on purpose: the register stopped updating them in 2012 and says not to rely on them.

What do DGR and ACNC mean?

A deductible gift recipient (DGR) is an organisation the ATO has endorsed so that donations to it are tax deductible; the “item” is the category of the endorsement. The ACNC is the Australian Charities and Not-for-profits Commission, and “registered” means the entity is a registered charity. Both appear only on records that have them, so most businesses show neither.

Why does a name search leave out cancelled ABNs?

Most people are checking a business that’s trading now, so the search shows active ABNs by default. Untick “Active ABNs only” to include cancelled ones, for instance to find a supplier that has since closed. You can also narrow a search to one state or territory.

Can I look up lots of ABNs at once?

No. The register is a free public service, so to protect it this tool does one lookup at a time, a few a minute and up to 100 a day for each visitor. For larger checks, the register itself offers bulk tools at abr.business.gov.au.

What an ABN lookup tells you

When to check an ABN

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