How BAS lodgement works, step by step
A Business Activity Statement (BAS) reports the GST you have collected and paid to the ATO, usually every quarter. Here is what actually happens, step by step.
What a BAS actually reports
A BAS mainly reports two GST figures: 1A (GST you collected on sales) and 1B (GST you paid on business purchases). The difference is what you owe the ATO, or what gets refunded to you.
If you employ staff or pay yourself PAYG instalments, those figures are reported on the same form — so a BAS can cover GST alone, or GST plus PAYG, depending on how your business is set up.
When it is due
Most small businesses lodge quarterly, with the statement due about four weeks after the quarter ends (28 October, 28 February, 28 April, 28 July). Registered tax and BAS agents often get extended deadlines.
Some larger businesses lodge monthly instead — the ATO sets your cycle when you register for GST.
Making it less painful
The classic BAS scramble happens when GST tracking is left until the deadline. Categorising transactions as they happen — rather than reconstructing three months of receipts — is what turns a BAS from a stressful afternoon into a five-minute review.
Fin tracks GST on every transaction as it lands, so your BAS figures are ready whenever the quarter ends, not assembled after the fact.
Take it further
Your quarterly GST position — 1A, 1B and the net amount payable, worked out for you.
BAS (Business Activity Statement) →The form GST-registered businesses use to report GST and PAYG.
GST (Goods and Services Tax) →Australia’s flat 10% tax on most goods and services.
PAYG (Pay As You Go) →Paying tax through the year rather than in one lump.
Common questions
Do I need to lodge a BAS if I have no GST-registered sales?
If you are registered for GST, you generally still need to lodge a "nil" BAS even in a quarter with no activity — check your specific obligations with the ATO or your accountant. This is general information, not personal tax advice — check what applies to you with your accountant or the relevant tax authority.
Can I lodge my BAS myself?
Yes — you can lodge directly through the ATO’s Business Portal or myGov, or via a registered BAS/tax agent. Keeping GST tracked through the quarter makes a self-lodged BAS straightforward.
What happens if I lodge late?
The ATO can apply a Failure to Lodge penalty for late BAS lodgement, calculated per 28-day period overdue. Lodging on time — or requesting an extension in advance — avoids this. This is general information, not personal tax advice — check what applies to you with your accountant or the relevant tax authority.
More on tax & compliance
Sole traders can generally claim any expense genuinely incurred in running the business. Here are the categories that come up most often.
GST vs VAT: what is the difference?GST and VAT are close cousins — both are consumption taxes added at the point of sale — but the name, rate and rules shift by country.
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