GST Calculator (Australia)

Work out GST at the standard 10% rate. Enter an amount, choose whether it already includes GST, and get an instant breakdown.

Net amount (excl. GST) $0.00
GST (10%) $0.00

Total $0.00

How to Calculate GST in Australia

Australia's Goods and Services Tax is a flat 10% added to most goods and services. There are two common situations, and the formula is different for each.

Adding GST to a price (GST exclusive)

If you have a price before tax and need to add GST, multiply by 1.1.
Example: A $100 item becomes $110 once GST is added. The GST component is $10.

Removing GST from a price (GST inclusive)

If you have a total that already includes GST and need to know how much of it is tax, divide by 11.
Example: A $110 total includes $10 of GST ($110 ÷ 11 = $10), and the underlying price before tax was $100.

The GST Formula, Summarised

To findFormula
GST amount from a GST-exclusive pricePrice × 0.10
Total price including GSTPrice × 1.1
GST amount within a GST-inclusive totalTotal ÷ 11
Net price with GST removedTotal ÷ 1.1

When GST Does Not Apply

Not every sale in Australia is subject to GST. Some goods and services are GST-free — most basic food, many medical and health services, and some education courses among them. Others are input-taxed, such as residential rent and some financial services, which works differently again.

This calculator uses the standard 10% rate that applies to most everyday transactions. If you're not sure whether GST applies to what you're selling, the ATO's own guidance is the authoritative source to check.

GST Calculator — Frequently Asked Questions

The standard rate is 10%, applied to most goods and services sold in Australia.

Multiply the price before tax by 1.1 to get the total including GST, or multiply by 0.10 to find just the GST component.

Divide the GST-inclusive total by 11 to find the GST component, or by 1.1 to find the price before GST.

It calculates the standard 10% rate correctly for everyday use. For BAS lodgement, always confirm figures with your bookkeeper or accountant, particularly where GST-free or input-taxed items are involved.

Only businesses registered for GST need to charge it — generally required once turnover exceeds the ATO's registration threshold. Check the ATO's current guidance for your specific situation.

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