GST Calculator Australia
Add or Remove 10% GST — and Estimate Your BAS

Adding GST: price × 1.1 (or price + 10%). Working out the GST in a price that already includes it: price ÷ 11.

Removing GST: price ÷ 1.1, or price × 10 ÷ 11. For example $110.00 includes $10.00 GST and is $100.00 before GST.

Because the 10% is charged on the price before GST, not on the total. A $100 item costs $110 with GST, and $10 is one-eleventh of $110.

Taking 10% off $110 would give $99, which is wrong.

When your GST turnover (gross business income, not profit) reaches $75,000 a year — counting either the current month plus the previous 11, or the current month plus the next 11 — you must register within 21 days. Non-profits register at $150,000.

Taxi, limousine and ride-sourcing drivers must register from the first dollar, and you must be registered to claim fuel tax credits. Below the threshold, registration is optional (and usually for at least 12 months).

Some sales have no GST, such as most basic food, some health and medical services, some education courses and childcare, and exports. Other sales are input-taxed (for example residential rent and most financial supplies): no GST is charged, but you can't claim GST credits on the costs of making them.

Generally, the GST you collected on your sales (label 1A) minus the GST credits on your business purchases (label 1B). If credits are larger, you get a refund.

You can only claim credits with a valid tax invoice for purchases over $82.50 including GST.