How do you calculate GST in Australia?

To add 10% GST to an exclusive price in Australia, multiply the net amount by 1.10. For example, $100 * 1.10 = $110 inclusive of GST (the GST amount is $10).

How do you calculate GST backwards (remove GST from a total)?

To calculate the GST component from a GST-inclusive price, divide the total price by 11. For example, if an item costs $110 inclusive of GST, $110 / 11 = $10 GST, and the net price before tax is $100.

When must an Australian business register for GST?

According to the Australian Taxation Office (ATO), you must register for GST if your business or enterprise has a GST turnover of $75,000 or more ($150,000 or more for non-profit organizations), or if you provide taxi, limousine, or ride-sourcing services (such as Uber or DiDi) regardless of turnover.

What items are GST-free in Australia?

Most basic foods (fresh fruit, vegetables, milk, meat, bread), most medical services and prescription medicines, certain educational courses and materials, child care, and export sales are GST-free under Australian tax law.

Do I need to issue a tax invoice for sales under $82.50 in Australia?

For taxable sales under $82.50 (inclusive of GST), businesses are not legally required to provide a formal tax invoice unless the customer specifically requests one.

🧾

Australian GST Calculator

ATO 10% Standard

Calculate GST-inclusive and GST-exclusive prices instantly with complete invoice breakdown.

Net Amount (Excluding GST)

GST Rate (%)10% (Australia ATO)

Calculation BreakdownAdding GST

Total Price (GST Inclusive)

$110.00AUD

Net Exclusive Amount:$100.00

GST Amount (10%):$10.00

Formula: $100.00 × 1.10 = $110.00 (GST Component = $100.00 × 10% = $10.00)

Multi-Item Tax Invoice Builder

Calculate itemized quotes, business receipts, or client invoices with auto-summed GST.

Item Description	Qty	Unit Price (Ex. GST)	GST (10%)	Line Total
Subtotal (Excluding GST):			$0.00
Total GST:			$0.00
Invoice Grand Total (Inc. GST):			$0.00

GST calculation adheres to Australian Taxation Office (ATO) rounding guidelines.

Official ATO Guidelines

How to Calculate GST in Australia: Formulas, Rules & Examples

The Goods and Services Tax (GST) is a broad-based consumption tax of 10% applied to most supplies of goods, services, and other items sold or consumed in Australia. Whether you are invoicing clients as a sole trader or verifying an expense receipt, understanding both forward and reverse calculations ensures your Business Activity Statement (BAS) remains 100% compliant.

Formula: Adding GST (Exclusive → Inclusive)

To calculate the final retail price when you know the net amount excluding GST:

GST Amount = Net Amount × 0.10

Total (Inc. GST) = Net Amount × 1.10

Example: If your consulting service is $250.00 excluding GST:
GST = $250.00 × 0.10 = $25.00
Invoice Total = $250.00 × 1.10 = $275.00

Formula: Removing GST (Inclusive → Exclusive)

To extract the GST portion from a gross price (calculating GST backwards):

GST Amount = Total Amount ÷ 11

Net (Ex. GST) = Total Amount ÷ 1.10

Example: If you paid a receipt total of $110.00 inclusive of GST:
GST component = $110.00 ÷ 11 = $10.00
Net business expense = $110.00 − $10.00 = $100.00

When Must You Register for GST in Australia?

Under ATO regulations, registration for GST is mandatory under specific turnover thresholds. If your turnover reaches or exceeds these figures in any 12-month period, you must register within 21 days:

Entity Type / Operation	Turnover Threshold	Requirement
Sole Traders, Freelancers & Businesses	$75,000 / year	Mandatory once projected or current gross income reaches $75k.
Non-Profit Organizations & Charities	$150,000 / year	Mandatory if annual gross revenue exceeds $150k.
Ride-Sourcing (Uber, DiDi, Ola) & Taxi Drivers	$0 (From first dollar)	Compulsory from day one, regardless of your total annual earnings.
Claiming Fuel Tax Credits	Any turnover	Required if you intend to claim fuel tax credits for business operations.

Frequently Asked Questions About Australian GST

Why is the GST divide formula 11 instead of 10?↓

When GST of 10% is added to a $100 price, the new total is $110 (110% of the original price). The GST itself ($10) represents 10 parts out of 110 total parts, which simplifies to exactly 1/11 (or 9.0909%) of the final retail price. Therefore, dividing the GST-inclusive price by 11 yields the exact GST dollar amount every time.

What items are exempt from GST (GST-free) in Australia?↓

The ATO designates several categories as GST-free: basic human foods (unprocessed fruit, vegetables, fresh milk, unflavoured bread, raw meat), most medical and dental services, doctor consultations, prescription medicines, accredited educational courses, child care services, and international sales/exports.

What information must appear on an Australian Tax Invoice?↓

For sales between $82.50 and $1,000, your tax invoice must show: (1) words stating it is a "Tax Invoice", (2) seller's business identity and Australian Business Number (ABN), (3) date of invoice issue, (4) brief description of items/services sold, (5) GST amount payable, and (6) the extent to which each sale is taxable. Invoices over $1,000 must also explicitly display the buyer's identity or ABN.

Can I claim GST back on business expenses if not registered?↓

No. You can only claim GST credits (input tax credits) on purchases you made for your business if you are registered for GST with the ATO and have valid tax invoices for purchases over $82.50. If you are not registered, you cannot claim GST credits, but the entire cost (including GST) may be deductible as an income tax business expense.