What GST Is, and Who Actually Pays It
Australia’s Goods and Services Tax is a broad-based 10% tax on most goods and services sold or consumed in the country. It began on 1 July 2000 and the rate has not changed since, which makes it one of the longest-unchanged headline tax rates in the developed world.
The mechanism is worth understanding because it explains why registered businesses treat GST so differently from consumers. GST is collected at every stage of the supply chain, but each registered business claims back the GST it paid on its own purchases. The tax passes through them and lands, in full, on the final consumer. For a business, GST is a cash-flow obligation rather than a cost; for everyone else, it is simply part of the price.
The Arithmetic People Get Wrong
Adding GST is straightforward: multiply by 1.1. Removing it is where invoices go wrong, because the instinct is to subtract 10%, and that is wrong every time.
An amount of $110 including GST does not become $99 when you subtract 10%. It becomes $100, because the 10% was calculated on the smaller number.
- Adding GST: exclusive × 1.1 = inclusive. $100 × 1.1 = $110.
- Removing GST: inclusive ÷ 1.1 = exclusive. $110 ÷ 1.1 = $100.
- The GST portion directly: inclusive ÷ 11. $110 ÷ 11 = $10.
That last one is the shortcut Australian bookkeepers use, and it is worth committing to memory. Because the rate is exactly 10%, the GST inside any inclusive amount is exactly one eleventh of it. No decimals, no rounding decisions: just divide by eleven.
| GST-exclusive | GST (10%) | GST-inclusive |
|---|---|---|
| $100.00 | $10.00 | $110.00 |
| $500.00 | $50.00 | $550.00 |
| $909.09 | $90.91 | $1,000.00 |
| $4,545.45 | $454.55 | $5,000.00 |
The bottom two rows are the useful ones: they start from a round inclusive figure, which is how prices are quoted to consumers, and show the untidy exclusive amount underneath.
What Is GST-Free
The 10% does not apply to everything, and the exceptions are broader than in many comparable systems:
- Basic food. Unprocessed items such as bread, milk, meat, fruit and vegetables. Prepared and restaurant food is taxed, and the boundary between the two has generated a well-known body of rulings.
- Most medical and health services, along with many medicines.
- Education courses and associated materials.
- Exports, provided they leave Australia within the required period.
- Some childcare and religious services.
The distinction that matters administratively is between GST-free and input taxed. A GST-free supply carries no GST and the supplier can still claim credits on related costs. An input taxed supply, which covers residential rent and most financial services, carries no GST and gives no right to claim those credits. The label is quiet about it, but the difference decides whether a business recovers the GST on its own expenses.
Registration and the BAS
Registration is compulsory once annual turnover reaches $75,000, or $150,000 for a non-profit. Below that it is optional, and voluntary registration lets you claim GST credits on business purchases. That can be worth it when equipment or stock costs are substantial, and is a poor trade when your customers are consumers who cannot claim the extra 10% back.
Once registered, you report through the Business Activity Statement, usually quarterly. You remit the GST collected on sales less the GST paid on purchases, and where purchases exceed sales the ATO refunds the difference.
The habit worth forming is treating collected GST as money you are holding rather than money you have earned. It is the single most common cash-flow mistake among newly registered small businesses: the quarter’s revenue looks healthy until the BAS falls due and a tenth of it turns out to have belonged to the ATO all along.
None of the above is tax advice. Thresholds and rules change, and the ATO’s own guidance or a registered tax agent is the right source where a figure has consequences.