GUIDES · AUSTRALIA
How to do your BAS
Your business activity statement (BAS) reports GST and other amounts to the ATO. Most of the work is getting the books right before you fill it in.
General information only, not accounting, tax or legal advice. Check with your accountant or the ATO where a decision depends on your circumstances. Written 30 October 2026 · last checked 30 October 2026.
Before you start
- Reconcile every bank account to the end of the period.
- Make sure every sale and purchase has the right GST code.
- Check for invoices or bills dated in the period that haven't been entered.
The GST figures
- Total sales (G1), GST on sales (1A) and GST on purchases (1B) come from your ledger for the period.
- Use the accounting basis you're registered for (cash or accruals).
Lodging
Lodge through ATO Online services, Online services for business, or your registered BAS or tax agent, by the due date on your statement.
In Plain
Plain prepares the BAS figures from your ledger and shows the transactions behind each one. You lodge through your usual channel.
Official source
Try it
Load the sample data in the demo and open the BAS figures.