Free • Instant • Add or Remove GST

GST Calculator Australia

Add 10% GST to a price, or remove GST from a GST-inclusive amount. Instant calculation with a clear breakdown.

GST Calculator

Amount (excluding GST)

Amount (ex. GST)—

GST (+10%)—

Total (inc. GST)—

GST is a 10% tax applied to most goods and services sold in Australia. There are two common calculations:

Multiply the pre-GST price by 1.1, or multiply by 0.1 to find the GST amount.
Example: $500 × 1.1 = $550 total (GST = $50)

Divide the GST-inclusive price by 11 to find the GST component.
Example: $550 ÷ 11 = $50 GST (pre-GST = $500)

Quick formula summary:

Add GST: amount × 1.1

Find GST in inc. price: amount ÷ 11

Remove GST: amount ÷ 1.1

Australian businesses can quote prices either way, but you must be clear about which one you are using.

GST-exclusive (“+ GST”)

Your quoted price does not include GST. GST is added on top at payment. Common in B2B contexts where clients claim it back.

e.g. $1,000 + GST = $1,100 total

GST-inclusive (“inc. GST”)

The quoted price already includes GST. The GST component must still be shown on your tax invoice.

e.g. $1,100 inc. GST (GST = $100)

AusInvoice supports both methods — just toggle the pricing mode when creating your invoice. Learn more →