To check a supplier's ABN and GST on an invoice, confirm the 11-digit ABN is valid and active on ABN Lookup (abr.business.gov.au), that the business is registered for GST, and that the invoice shows the details a tax invoice needs. LedgerSnaps runs this check automatically when it reads each bill.

What to look for on the invoice

For a taxable sale of less than A$1,000, the ATO says a tax invoice must make these details clear:

• The document is intended to be a tax invoice
• The seller's identity and ABN
• The date the invoice was issued
• A brief description of the items sold, including the quantity (if applicable) and the price
• The GST amount, shown separately or, if it is exactly one-eleventh of the total price, a statement that the total price includes GST
• The extent to which each sale on the invoice is taxable

For sales of A$1,000 or more, the invoice must also show the buyer's identity or ABN. A supplier only has to provide a tax invoice if you ask for one, unless the sale is A$82.50 (including GST) or less. Source: ATO: Tax invoices (last updated 18 September 2026).

This guide is general information and not tax advice. Check the ATO page above for the current requirements.

How to check an ABN yourself

1. Go to ABN Lookup and search the ABN.
2. Check the ABN is active and not cancelled.
3. Check whether the entity is registered for GST, and from what date.
4. Check the registered name matches the supplier on the invoice.

A quick sanity check: the ABN checksum

An ABN has 11 digits and a built-in checksum. Subtract 1 from the first digit, multiply each digit by the weights 10, 1, 3, 5, 7, 9, 11, 13, 15, 17, 19, add the results, and the total must divide evenly by 89. A failed checksum means the number was mistyped or is not a real ABN. A passing checksum does not prove the ABN is active, so still look it up.

Why it matters

If a supplier is not registered for GST, the invoice should not charge GST. If an ABN is wrong or missing, claiming the GST credit can be at risk. Catching these when you enter the bill is far easier than fixing them at BAS time.

Automating it in LedgerSnaps

When LedgerSnaps extracts a bill, it looks up the supplier's ABN in the Australian Business Register and shows whether the ABN is valid and whether it is registered for GST. Warnings appear next to the bill during review and lower its confidence score. It is a helpful check, not tax advice.

Frequently asked questions

Related guides

• How to import supplier invoices into Xero
• Choosing invoice automation for Xero: a checklist for Australian businesses

Last updated: 2026-11-04 · General information only, not tax or accounting advice.