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GST

How to calculate GST

Last Updated on 20/07/2026
Written by Oliver Gye
Fact Checked
4 minutes read
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Key Takeaways (TL;DR)

  • GST is 10% of the base price; add GST by multiplying by 1.1, or work out the GST component from a GST-inclusive amount by dividing by 11.
  • Businesses generally must register for GST when annual turnover reaches $75,000, or $150,000 for not-for-profits.
  • GST-registered businesses report GST collected and paid through their BAS, and may receive GST credits if they have paid more GST than they collected.

Calculating the goods and services tax (GST) is a fundamental part of running a business in Australia. For businesses, it is essential to get GST right, as failing to calculate GST properly can have a wide range of consequences and penalties from the Australian Taxation Office (ATO). To calculate GST, simply multiply your figure by 1.1 for inclusive or divide by 11 for exclusive GST amounts. Whether you’re a sole trader or a company, here is how you can accurately calculate GST for your business.

How is GST calculated?

The GST rate is 10% of the base cost. If you have paid for any product or service in Australia, you’ve likely paid GST. There are two ways to determine the GST amount for a good or service. If you are trying to find the total price including GST, you multiply the figure by 1.1.

GST Inclusive Formula

GST INCLUSIVE =

100 x 1.1 =

110 (GST inclusive price)

GST inclusive formula

GST Exclusive Formula

If you are looking for the total price excluding GST, then you divide the price including GST by 11 and subtract:

GST EXCLUSIVE =

100 / 11 =

90.90 (GST exclusive amount)

9.09 GST amount

GST exclusive price formula

GST Turnover thresholds

Handling GST is part of running a business. Under the Australian Tax Office (ATO)’s mandate, businesses that generate $75,000, or $150,000 for non-profit organisations, meet the threshold and must be registered for GST. Those that earn below the threshold (GST turnover) aren’t required to charge GST on invoices they send out, and can also request bills they receive to exclude the GST component. However, GST-registered businesses will often request GST be added to transactions for tax reasons, like when they file their business activity statement.

What are GST credits?

GST credits are part of a tax compliance system administered through business activity statements (BAS). Essentially, during operation, a business collects and pays GST on various transactions. When a business’s BAS is due, the company calculates the GST it paid and collected during the financial period. Depending on how much GST is involved, you can either get a refund (GST credits) from the ATO or owe them (GST payable) if you collect more GST than you paid.

How to claim GST credits?

To claim GST credits, you first need to complete your BAS and send it to the ATO for review. Once reviewed, if it is found that you paid more GST than you collected in your BAS, the ATO will refund you the amount.

GST calculations and your business

GST is an important tax that small business owners need to understand, as it has far-reaching effects on how you operate, how you charge, and how you file your taxes (Business Activity Statement). To make sure that you calculate GST correctly, here is our GST Calculator. If you want to eliminate manual entry admin time from your accounts and bookkeeping, Reckon software can help you automatically calculate GST.

About the Author

Oliver Gye

Content Writer
Oliver Gye is a content writer and publisher who is passionate about creating engaging content for the small business community. He specialises in UX, business support & compliance, and small business journalism in fintech and accounting.

Oliver Gye

Content Writer
Oliver Gye is a content writer and publisher who is passionate about creating engaging content for the small business community. He specialises in UX, business support & compliance, and small business journalism in fintech and accounting.

Download your free GST guide

GST guide

There’s a lot to get your head around when you’re starting a new business, and GST is just one bit most fledgling business owners will need to get to grips with. If you’re looking for help, download our free guide to better understand GST.

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