Free Australian GST calculator. Instantly add or remove 10% GST from any amount. Perfect for invoicing, quoting, and business accounting. Shows the GST-exclusive amount, GST component, and GST-inclusive total.
GST Exclusive
$0.00
GST (10%)
$0.00
GST Inclusive
$0.00
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The Goods and Services Tax (GST) is a broad-based 10% tax on most goods, services, and other items sold or consumed in Australia. If your business is registered for GST, you need to include GST in the price of most goods and services you sell, and you can claim credits for the GST included in the price of goods and services you buy for your business.
Australia's GST rate is a flat 10%, so the maths is simple:
Worked example. You quote a job at $500 before tax. Adding GST: $500 × 1.1 = $550, of which $50 is GST ($500 × 0.10). If a supplier instead gives you a $550 GST-inclusive invoice, the GST component is $550 ÷ 11 = $50, and the GST-exclusive cost is $550 ÷ 1.1 = $500.
When you lodge your BAS, you report the GST you've collected on sales (label 1A) and the GST you've paid on purchases (label 1B). The difference is either paid to the ATO or refunded to you. Most businesses lodge BAS quarterly, though some lodge monthly or annually.
You must register for GST if your annual turnover is $75,000 or more ($150,000 for non-profit organisations). Once registered, you must charge GST on your taxable sales, lodge regular BAS, and keep GST records for at least five years.
GST in Australia is a flat 10% on most goods and services. It has stayed at 10% since it was introduced on 1 July 2000. So a $100 GST-exclusive sale carries $10 of GST, making the GST-inclusive price $110.
To work out the GST amount on a GST-exclusive price, multiply it by 0.10 (10%). To work out the GST already included in a GST-inclusive price, divide the total by 11. For example, the GST inside a $110 price is $110 / 11 = $10.
GST (Goods and Services Tax) is a 10% tax on most goods, services, and other items sold or consumed in Australia. It was introduced on 1 July 2000. Businesses registered for GST collect it from customers and remit it to the ATO.
To add GST, multiply the GST-exclusive amount by 1.1. For example, $100 + GST = $100 x 1.1 = $110.
To remove GST, divide the GST-inclusive amount by 11 to get the GST component, then subtract it. Or simply divide the GST-inclusive price by 1.1. For example, $110 / 1.1 = $100 ex-GST.
You must register for GST if your business has a GST turnover of $75,000 or more per year ($150,000 for non-profit organisations). Taxi, limousine and ride-sourcing drivers (Uber, DiDi, Ola, etc.) must register for GST regardless of turnover — even on their first fare. You can voluntarily register if your turnover is below the threshold.
Some items are GST-free, meaning no GST is charged. Examples include most basic foods, some education courses, some medical services, and exports. These are different from input-taxed items like financial supplies and residential rent.
An input tax credit (also called a GST credit) is the GST you can claim back on the business purchases you use to run your enterprise. If you are registered for GST, you offset the GST you collect on sales (output tax, BAS label 1A) against the GST you paid on purchases (input tax credits, BAS label 1B); you only pay the ATO the difference. You generally need a valid tax invoice to claim a credit on a purchase over $82.50 (including GST).
Sources & methodology
This tool applies Australia's flat 10% GST rate (unchanged since 1 July 2000): to add GST it multiplies the GST-exclusive amount by 1.1, and to remove GST it divides the GST-inclusive amount by 11 for the GST component. Figures are computed in your browser — nothing you enter is stored or sent to a server.
Authoritative sources
Reviewed by Bishal Shrestha — Founder of OneBookPlus, 10+ years building tools with Australian tax-agent and BAS-agent practices. Last reviewed and updated: May 2026.
Disclaimer: This calculator produces estimates only and is not tax advice. Tax outcomes depend on your individual circumstances. For decisions that affect your tax position, consult a registered tax agent or the ATO directly.
OneBookPlus handles invoicing, GST tracking, BAS prep, and ATO lodgement automatically.
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