BAS & GST Quarterly Estimator
Know what you owe the ATO — before they tell you
Plug in your quarter's sales and purchases. We'll estimate GST payable, optional PAYG instalments, and show your due date.
Your quarter
Use totals including GST where it applies (that's how the ATO asks for them on the BAS form).
Cash = money in/out. Accrual = invoice issued.
All invoices you collected/issued this quarter.
Exports, basic groceries, some medical — usually $0 for trades.
Parts, fuel, subs, phone, software — the day-to-day stuff.
Tools, van, equipment over $1,000. Claim full GST upfront.
Bank fees, insurance (some), wages — these don't have GST to claim.
If you pre-pay income tax via PAYG-I, put the amount here.
Total tax withheld from wages paid this quarter.
Estimated net amount to the ATO
$0
Set aside now — BAS due 28 Apr.
What to put on your BAS form
| Label | What it's called | Amount |
|---|
Get BAS reminders before every due date
We'll email you 14 and 3 days before each BAS deadline so you never get an ATO late fee again.
Quick facts for AU trades
- GST is 10% flat. Divide by 11 to get GST from a GST-inclusive total.
- You must register for GST if your turnover is $75,000+ (or expected to be).
- BAS is due on the 28th of the month after the quarter ends (or 25 Feb for Q2).
- Lodge and pay via myGov, ATO Online Services, or your tax agent.
- Late lodgement = failure-to-lodge penalty (currently $330+ per 28 days).
- A good rule: transfer 1/11th of every payment received into a separate GST account as you go.
This tool is a rough estimate — not tax advice. Your accountant or the ATO is the source of truth.
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