How to Check a Contractor's ABN (and the 47% No-ABN Withholding Rule)

Before you pay a contractor, you need their Australian Business Number (ABN). Getting the number is easy. Knowing it is real, still active, belongs to the person invoicing you and matches their GST status is the part that changes what you pay.

This post covers how to check an ABN, what happens when a supplier does not give you one, and how to keep a record of the check in WorkZerk.

Why an ABN is worth checking

An ABN that has been cancelled, belongs to a different business or is not registered for GST changes the payment:

• No valid ABN can mean withholding. If a supplier does not quote an ABN, you generally have to withhold tax from the payment (more on that below). The ATO says the same applies if the ABN you were given is invalid or does not belong to the supplier (Checking an ABN).
• GST depends on registration. You can only claim a GST credit if the supplier is registered for GST (When you can claim a GST credit).

The ATO says you generally do not need to check an ABN that looks right, but you should check one if you suspect it is not genuine or not the supplier's own (Checking an ABN).

How to use ABN Lookup

ABN Lookup is the free public view of the Australian Business Register. Search by the 11-digit number and the record shows:

• ABN status: Active or Cancelled, with the date that status started (for example "Active from 01 Jul 2013").
• Entity name: the legal name. For a sole trader this is the person's own name.
• Goods & Services Tax (GST): whether the entity is registered, and the date the registration started.
• Business name(s): names registered with ASIC, each with its own "from" date.

A Historical details tab shows earlier statuses and names. Trading names are less reliable: the ABR stopped collecting them in 2012 (Business names and trading names FAQs).

Matching the ABN to the invoice

Once you have the record, compare it with the contractor's invoice:

1. The status is Active.
2. The name on the invoice is the entity name or one of its current business names.
3. If the invoice adds GST, the entity was registered for GST on the invoice date.

If something does not line up, ask the contractor before you pay.

When a supplier does not give you an ABN

If a supplier does not provide an ABN and the total payment is more than $75 (excluding GST), you generally withhold the top rate of tax and pay it to the ATO (Withholding if ABN is not provided). That rate is 47% (Withholding from suppliers).

If a supplier has applied for an ABN, you can hold the payment until they quote it, but you must not pay in full on the promise that the ABN will come later.

There are payments you do not have to withhold from, even without an ABN (Payments you don't withhold from). They include:

• a payment of $75 or less, excluding GST, for the whole supply
• a supplier who is an individual under 18, paid $350 or less a week
• a supply made as a hobby or private recreational pursuit, or one that is wholly private or domestic for the supplier

For the last case, the supplier can give you a Statement by a supplier. Someone running a business or entitled to an ABN cannot use it. Keep the statement for five years.

GST and tax invoices

If an invoice adds GST, check the GST line on ABN Lookup first: you cannot claim a GST credit from a supplier who is not registered. For a purchase over $82.50 including GST, you also need a valid tax invoice, which shows the supplier's ABN (Tax invoices).

The taxable payments annual report

Businesses that pay contractors for certain services may need to lodge a taxable payments annual report (TPAR) by 28 August each year. The services covered are building and construction, cleaning, courier, road freight, information technology, and security, investigation or surveillance (Payments businesses need to report in their TPAR).

It lists each contractor's ABN, name, address and what you paid them, and the ATO asks you to check those details with ABN Lookup (TPAR contractor details to report).

An ABN does not make someone a contractor

Having an ABN makes no difference to whether a worker is an employee or a contractor. If the arrangement is employment, an ABN does not change that (ATO myths and facts).

Checking again later

An ABN does not expire, but it can be cancelled, and GST registration can start or stop. For contractors you pay regularly, a periodic re-check (yearly, say, and before your TPAR) catches a change before it reaches an invoice. Record the date of each check.

This is general information, not legal or tax advice. Check the ATO pages linked above, or ask your accountant, for your own situation.

What WorkZerk does with an ABN

WorkZerk keeps the contractor's details and your check in one place:

• Each contractor enters their ABN, legal or business name and GST status from a private link on their phone, with no account or password.
• The answers are saved to their contact record, next to a Date field where your team records when they checked the ABN.
• The Contacts report lists everyone with a column for each field, including the ABN and the date it was checked, and downloads as a CSV.

What it does not do: WorkZerk does not look up the ABN on the Australian Business Register, confirm GST registration, or work out withholding. The lookup stays with you; WorkZerk records that you did it. An ABN is not a document, so it is not in the Document compliance report.

Setting it up in WorkZerk

1. Start from the contractor pack

Open Requests (opens in WorkZerk in a new tab), click Request packs, open Start from a template, and add Contractor onboarding (Australia). It already asks for an ABN, saved to an ABN field on the contact, and asks Are you registered for GST?, along with insurance, licences and bank details. See starter request packs.

The pack includes uploads, so turn on two-factor authentication for your account before you add it to a portal.

2. Add the fields for your check

Open Fields (opens in WorkZerk in a new tab) in the sidebar and add:

• Legal or business name, a Text field.
• GST registered, a Choice field with the options Yes and No.
• ABN checked on, a Date field your team fills in after each lookup.

The pack's GST question is a plain Choice ask, so its answer stays with that portal. To keep GST status on the contact record, replace it with a Fields request for your GST registered field. See custom contact fields.

3. Create a portal, or use the one you have

Open Portals (opens in WorkZerk in a new tab) and click New portal, or use an onboarding portal you already run. Add the pack from the portal's Requests panel, then a Fields request for Legal or business name.

Optionally, click + Insert, choose Upload, and name it "Statement by a supplier (only if you have no ABN)". Set Min files to 0 so it is optional, and use Attach a document, link or YouTube video to link the ATO's form.

4. Add your people

Add contractors to the portal and send each one their private link, or share the portal's self-registration link.

5. Check each ABN and record it

When a contractor's answers arrive:

1. Look up their ABN on ABN Lookup.
2. Check the status, the name and the GST registration against what they entered.
3. If anything does not match, contact them before you pay.
4. Enter today's date in ABN checked on on their contact record.

6. See who is due for a re-check

Open Reports, then Contacts (opens in WorkZerk in a new tab). Each field is a column, so every ABN, GST status and ABN checked on date sits side by side. Use Download CSV to sort by the check date, or to hand the list to your bookkeeper at TPAR time.

Getting started

Start a free WorkZerk trial at workzerk.com, then work through the steps above. If you get stuck, the getting started guide walks through a first portal end to end, or email us at [email protected].