Active ABNs only State Filters apply to name searches.

Try 51 824 753 556 (the ATO). A 9-digit ACN or part of a business name works too. Free, no account needed.

Your lookup goes from your browser to the tools server of Digital Greenhouse, the company that runs Chill Domains, and from there to the Australian Business Register. Nothing you type is stored: the register’s answer is held for 15 minutes so repeat lookups don’t bother it, and your IP address is used only to limit how often lookups can be made. A number that fails its check digit is answered without asking the register.

Data from the Australian Business Register (ABN Lookup), as it stands when you look it up. This is our 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. It’s general information, not legal, tax or financial advice, and a lookup here isn’t a ruling on your eligibility for a domain: the registrar checks that at registration and renewal.

Register a .com.au → Search for your name. We check the ABN against the register before you pay. The ABN check at renewal → Why a .com.au on a cancelled ABN can be refused, and the fix. Domain toolbox → WHOIS, DNS, MX and SSL lookups for any domain.

Why check an ABN before you register a .com.au?

auDA, the body that runs .au, only lets an Australian commercial entity hold a .com.au or .net.au: a company (by its ACN), a sole trader, partnership or trust with an ABN, an incorporated association, or the holder of an Australian trade mark. When you register the name, the registrar checks the number you give against the Australian Business Register, and since 2026 .au renewals have been checked the same way. A cancelled or mistyped number means a refused registration, or a domain that can’t be renewed. Thirty seconds here saves that. Chill Domains checks the number against the same register at checkout, so a problem found now is a refused order avoided.

The number also has to belong to the right entity. The domain name must match or be an acronym of the entity’s name or a business name registered to it, or (for now) relate to goods or services it provides. If your business name sits on a different ABN from the one you were about to use, the lookup shows you which business names each ABN carries.

What the lookup shows

Every ABN 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 entity, 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 registered to it, each with its registration date. Where they apply, it also shows deductible gift recipient (DGR) endorsement, ACNC charity registration and when the record was last updated. Ask for the history and it adds previous names, previous locations and every change of ABN status, which is handy when a domain was registered years ago under a name the business no longer uses.

My ABN shows as cancelled. What happens to my .com.au?

Nothing today, but the next renewal can be refused and the licence cancelled, because you’re no longer eligible to hold the name. If the business is still trading, reactivate the ABN through the ATO, or apply for a new one. If the business now runs as a company or trust with a different number, the domain has to move to that entity through a change of registrant. At Chill Domains that renews the licence for a year under the new registrant, with whole years left carried over, and both the old and new registrant confirm by email. Do it well before the expiry date, not in the last week. Our guide to the ABN check at renewal has a table of which fix applies to which situation.

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. A domain registration quoting it will be refused until the register lists it, so wait for the lookup to find it before you buy.

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 passes is only well-formed, which is why the tool goes on to ask the register whether it exists, who holds it and whether it’s active.

Can a company register a .com.au with just its ACN?

Yes. A company registered with ASIC is eligible on its ACN alone, whether or not it has an ABN. Most companies have both, and the register links them, so an ACN lookup here shows the company’s ABN record. A company with no 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. For a .au domain, auDA’s WHOIS shows the registrant’s name and ABN or ACN, but not their address or phone number either.

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. A trading name that was never registered as a business name doesn’t count towards .com.au eligibility either.

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 the old ABN a domain was registered on. 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 the 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.

Where does the lookup run?

Through the tools server of Digital Greenhouse, the Sydney IT company that runs Chill Domains, which asks the Australian Business Register with its registered web-services account and passes the public record back. The same lookup is on the Digital Greenhouse site, with a focus on checking suppliers before you pay them. Neither keeps what you look up.