BAS (Business Activity Statement)
The form GST-registered businesses use to report GST and PAYG.
A BAS is the form you lodge with the ATO — usually each quarter — to report the GST you collected, the GST you’re claiming back, and any PAYG amounts. The difference between GST collected (1A) and GST paid (1B) is what you pay or get refunded.
Most small businesses lodge a BAS quarterly, due about four weeks after the quarter ends. Keeping GST sorted through the year makes each BAS a few taps instead of a scramble.
Worked example
Over a quarter you invoice $33,000 including GST, so GST collected (1A) is $3,000. You spent $11,000 including GST on supplies, so GST paid (1B) is $1,000. Your BAS shows $3,000 − $1,000 = $2,000 payable.
Common mistake
Claiming GST back on a purchase from a supplier who isn’t GST-registered. If there’s no GST on the invoice, there’s nothing to claim — which is exactly why a valid tax invoice matters.
Grounded in ATO guidance. Figures last checked . General information, not tax advice.
Related terms
GST (Goods and Services Tax)
Australia’s flat 10% tax on most goods and services.
PAYG withholding vs PAYG instalments
One is tax you hold back for others; one is prepaying your own.
Tax invoice
The GST-compliant invoice that lets a buyer claim the GST back.
PAYG (Pay As You Go)
Paying tax through the year rather than in one lump.
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Questions about this term
BAS (Business Activity Statement): common questions
- How often does a small business lodge a BAS?
- Usually each quarter. Most small businesses lodge a BAS quarterly, due about four weeks after the quarter ends, reporting the GST collected, the GST being claimed back, and any PAYG amounts. Keeping GST sorted as transactions arrive through the quarter is what turns the lodgment into a few taps rather than a scramble.
- How is the amount payable on a BAS worked out?
- It is GST collected minus GST paid. Label 1A holds the GST on your sales and 1B holds the GST on your purchases; the difference is what you pay or get refunded. Invoice $33,000 including GST and 1A is $3,000; spend $11,000 including GST on supplies and 1B is $1,000, so $2,000 is payable. The BAS calculator on this site runs those two figures for your own quarter.
- Can I claim GST on a purchase from a supplier who isn’t registered?
- No — if there is no GST on the invoice, there is nothing to claim back at 1B. A supplier who isn’t GST-registered doesn’t charge it, so treating their bill as if a tenth of it were GST overstates your credits. This is exactly why a valid tax invoice matters: it shows whether GST was charged and how much.
- Does a BAS only cover GST?
- No — a BAS reports the GST you collected and are claiming back, and also any PAYG amounts. That is where PAYG withholding and PAYG instalments land, which is one reason the two are so often confused: they share a form as well as a name. The GST section and the PAYG section are worked out separately on the same statement.
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