Work out your net GST position in seconds using the ATO's Simpler BAS method. If your GST turnover is under $10 million, you only report three fields each quarter: G1 (total sales), 1A (GST collected on sales) and 1B (GST paid on purchases).
Enter those three numbers and this free calculator shows your net payable or refund instantly, and flags figures that look off before they become an amendment.Built by Scale Suite, a registered BAS Agent (26298194).
Note this tool covers GST only. If you also pay staff or ATO instalments, our Quarterly BAS Calculator estimates your full BAS payment across GST, PAYG withholding, income tax instalments, FBT and Fuel Tax Credits.
Purpose:
This tool is built for Australian small businesses, sole traders and bookkeepers using the Simpler BAS reporting method, which covers any business with GST turnover under $10 million. It performs the core calculation on every quarterly activity statement (net GST equals 1A minus 1B) and gives you a fast pre-lodgement check.
Pull your figures straight from Xero's BAS Preview report, MYOB's GST return report or your software's equivalent, rather than estimating. Run it before every lodgement to verify the number your software produced, and monthly during the quarter if you want a rolling view of the GST you should be setting aside. Bookmark the page so it is there on BAS day.
Tips for Ongoing Use:
Bookmark this page (Ctrl+D or Cmd+D) for quick access during BAS lodgment. UBookmark this simplified BAS calculator Australia page before every BAS due date (quarterly deadlines: 28 October, 28 February, 28 April, 28 July). Pull figures directly from your Xero/MYOB reports for highest accuracy. Use it monthly for rolling estimates to improve cash flow planning.
What is Simpler BAS?
Simpler BAS has been the default GST reporting method for small businesses since 1 July 2017. If your GST turnover is under $10 million, you only report three labels:
- G1: Total sales. All business income for the period, GST-inclusive where applicable.
- 1A: GST on sales. The GST you collected on taxable sales.
- 1B: GST on purchases. The GST you paid on business purchases, claimed back as input tax credits.You no longer need to complete the extra labels on the full reporting method, including G2 (export sales), G3 (other GST-free sales), G10 (capital purchases) and G11 (non-capital purchases).
Businesses with GST turnover of $10 million or more stay on full BAS reporting.One thing Simpler BAS does not simplify: record keeping. You still need valid tax invoices for purchases over $82.50 (GST-inclusive) to claim credits, and you still need to classify sales correctly behind the scenes. Simpler BAS reduces what you report, not what you track.
What this calculator deliberately leaves out:
Simpler BAS covers GST only. A real quarterly BAS for a business with staff usually also includes PAYG withholding (W2), PAYG income tax instalments (T7), and sometimes FBT instalments and Fuel Tax Credits. Those lines are often bigger than the GST itself. To estimate the whole payment, use our Quarterly BAS Calculator.Superannuation is not on the BAS at all. From 1 July 2026, payday super rules apply: contributions must reach your employees' funds within 7 business days of each payday, replacing the old quarterly super deadlines.
BAS due dates for 2026-27:
Quarterly BAS is due on the 28th of the month after each quarter ends: 28 October 2026 (Q1), 28 February 2027 (Q2, which falls on a Sunday, so practically Monday 1 March 2027), 28 April 2027 (Q3) and 28 July 2027 (Q4).
Lodging online adds around two weeks on Q1, Q3 and Q4, and lodging through a registered BAS Agent adds around four weeks on the same quarters. Confirm your exact date with our BAS Lodgement Deadline Calculator.
Benefits for SMEs:
This calculator simplifies GST estimation, supports cash flow planning, and aids BAS compliance. Explore Scale Suite’s finance services for expert support. This tool is an estimate just for GST only and not tax advice. Consult a registered BAS or tax agent and confirm with the ATO for your specific situation, especially for complex transactions or other taxes. Simplifies GST estimation, supports proactive cash flow management, reduces lodgement stress and strengthens ATO compliance.
Additional Resources:
Explore Scale Suite’s resources for additional insights or review our Simpler BAS article here.
More Tools for Your Business: Finance & HR | Owner Toolkit
30 minutes with our team.
We'll review your current finance setup, compare the full cost of an internal hire against our embedded team, and show you exactly what your finance function should cost at your stage of growth.
You'll leave with a clear view of what's working, what's missing, and where you'd save.
No lock-in contracts. 30-day money-back guarantee.
Prefer to book directly? Grab a time here.
