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GST calculator

Add 10% GST to a price, or find the GST inside a price that already includes it. Australian GST, rounded to the cent, with the working shown.

Add or remove GSTShows the workingNo sign-up
Price excluding GST$100.00
GST (10%)$10.00
Price including GST$110.00

GST = $100.00 × 10% = $10.00.

Calculated on your device, rounded to the nearest cent.

How to add GST to a price

GST in Australia is 10% of the price before GST. To add it, multiply by 1.1 (or add 10%).

Example: a job priced at $450 excluding GST. GST is $450 × 10% = $45, so the price including GST is $495.

How to work out the GST in a GST-inclusive price

Because the GST-inclusive price is 110% of the price before GST, the GST is one eleventh of the total. Divide by 11.

Example: $495 including GST contains $495 ÷ 11 = $45 of GST, so the price excluding GST is $450.

Common mistake: taking 10% of a GST-inclusive price. 10% of $495 is $49.50, which overstates the GST by $4.50. Divide by 11 instead.

Quick reference

AmountGST if you add itTotal with GSTGST inside itAmount without GST
$50.00$5.00$55.00$4.55$45.45
$100.00$10.00$110.00$9.09$90.91
$250.00$25.00$275.00$22.73$227.27
$500.00$50.00$550.00$45.45$454.55
$1,000.00$100.00$1,100.00$90.91$909.09
$2,750.00$275.00$3,025.00$250.00$2,500.00

Rounding GST on invoices

GST is rounded to the nearest cent, with half a cent rounded up. When one tax invoice has several taxable items, the ATO allows two methods: total the items and work out GST once (the “total invoice rule”), or work out each item's GST and round the total (the “taxable supply rule”). This calculator and Krid's free invoice generator use the total invoice rule.

When you charge GST, and when you don't

  • You charge GST only if you're registered for GST (or required to be). You must register once your GST turnover reaches $75,000 a year ($150,000 for non-profits), and taxi and ride-sourcing drivers must register whatever their turnover.
  • Even when you're registered, some sales are GST-free or input-taxed. Show those clearly on your invoice.
  • If you're not registered, don't add GST and don't call your invoice a tax invoice. Our no-GST invoice template is set up for that.

Krid calculates GST for you when creating invoices.

GST is worked out on every line to the cent, GST-free items are shown properly and registered businesses get a proper Australian tax invoice.

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Questions

How do I add GST to a price?

Multiply the GST-exclusive price by 1.1, or add 10%. $200 plus GST is $200 + $20 = $220.

How do I work out the GST in a price that includes GST?

Divide the GST-inclusive price by 11. $220 including GST contains $20 of GST, so the price without GST is $200. Don't take 10% of the total: that overstates the GST.

What is the GST rate in Australia?

10% on taxable sales. Some sales are GST-free (for example most basic food, some medical and education services) and some are input-taxed, so check the ATO's guidance for what you sell.

Do I have to charge GST?

Only if you're registered for GST or required to be. You must register when your GST turnover is $75,000 or more a year, and in some industries regardless of turnover.

How should GST be rounded on an invoice?

To the nearest cent, rounding half a cent up. With several taxable items, the ATO lets you either total first and round once, or round each item's GST and then round the total.

More free tools

Invoice generator

Make a tax invoice or no-GST invoice and download a PDF.

Open

Tax invoice template

Word, Excel and PDF templates for GST-registered businesses.

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Tax invoice rules

What must be on a tax invoice, and when.

Open

Sources

Last reviewed 27 October 2026. General information for Australian businesses, not tax or legal advice. If you're unsure how a rule applies to you, ask the ATO or a registered tax agent.

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