Tool

GST Calculator Australia

Free Australian GST calculator. Add or remove 10% GST instantly. Works both ways: calculate GST-inclusive from ex-GST, or extract GST from a total.

How GST calculations work in Australia

Australia’s Goods and Services Tax is a flat 10% tax on most goods and services. The calculation depends on your starting point:

Adding GST (ex-GST to inc-GST)

GST amount = Ex-GST price × 0.10
GST-inclusive price = Ex-GST price × 1.10

Removing GST (inc-GST to ex-GST)

Ex-GST price = GST-inclusive price ÷ 1.10
GST amount = GST-inclusive price ÷ 11

Who needs to calculate GST?

GST calculations are part of daily business operations for:

Finance teams preparing invoices and processing payments
Bookkeepers reconciling transactions and coding expenses
Business owners pricing products and services
Accountants preparing BAS lodgements and tax returns

GST registration thresholds (FY2025-26)

Entity type	Turnover threshold
Standard business	$75,000 per year
Non-profit organisation	$150,000 per year
Taxi/ride-sharing drivers	Any turnover

Businesses below the threshold can register voluntarily to claim input tax credits on purchases.

Calculate GST

Amount ($)

Direction

$100.00 ex-GST amount

$10.00 GST (10%)

$110.00 inc-GST total

Frequently asked questions

How do I add GST to a price?

Multiply the ex-GST amount by 1.1. For example, $100 ex-GST becomes $100 × 1.1 = $110 inc. GST. The GST component is $10 (10% of the original price).

How do I remove GST from a price?

Divide the GST-inclusive amount by 1.1 to get the ex-GST price. Then subtract the ex-GST price from the original to find the GST component. For example, $110 ÷ 1.1 = $100 ex-GST, with $10 GST.

Do all Australian businesses need to charge GST?

Businesses with an annual turnover of $75,000 or more (or $150,000 for non-profit organisations) must register for GST and charge it on taxable supplies. Businesses below this threshold can choose to register voluntarily.

What is the difference between GST-inclusive and GST-exclusive pricing?

GST-inclusive pricing includes the 10% tax in the displayed price. GST-exclusive pricing shows the base price before tax. In Australia, consumer-facing prices are generally displayed GST-inclusive, while B2B pricing is often quoted ex-GST.

Methodology and disclaimer

This calculator uses the standard Australian GST rate of 10% as published by the Australian Taxation Office (ATO). Adding GST multiplies the ex-GST amount by 1.1. Removing GST divides the inclusive amount by 1.1.

This tool provides estimates only and does not constitute financial, tax, or legal advice. It does not account for GST-free items, input-taxed supplies, or special rules for specific industries. Always consult a registered tax agent or BAS agent for your specific circumstances. Rates are current as at 1 July 2025.

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