GST & Tax calculator
GST Calculator Australia
Add GST to a GST-exclusive amount or remove GST from a GST-inclusive amount with a simple Australian GST calculator.
Why use it
- Useful for quick quote checks, invoice checks, and GST-inclusive pricing.
- In add mode, the amount is treated as GST-exclusive. In remove mode, the amount is treated as GST-inclusive.
- This tool assumes the standard Australian GST rate of 10%.
Calculator tool
Use the gst calculator australia
Add GST to a GST-exclusive amount or remove GST from a GST-inclusive amount with a simple Australian GST calculator.
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Important note
BizTools.au is designed to make business numbers easier to check, but calculator outputs still need judgment and real-world context.
- Calculator results are general estimates only and depend on the figures entered.
- Examples and summaries are provided for general information, not legal, tax, accounting, payroll, or financial advice.
- Before relying on a result for a real decision, check your assumptions and get qualified advice where needed.
How it works
Understand the formula before you use the result
The calculator uses a simple working formula so you can sense-check the result quickly and explain it clearly inside your business.
GST calculator formula
Add GST: GST = amount × 10%
Add GST: gross amount = amount + GST
Remove GST: net amount = amount / 1.1
Remove GST: GST = amount - net amount
When removing GST, the entered amount is treated as GST-inclusive. The GST component is backed out from the total.
Worked example
See the numbers in a realistic scenario
Use the example below as a sense check when you compare the calculator result to a real quote, sale, or pricing decision.
Worked example
Worked example: checking a GST-inclusive invoice
A business receives an invoice total of $1,100 and wants to separate the GST from the GST-inclusive amount.
- Amount: $1,100
- Mode: Remove GST
Calculation steps
- Net amount = $1,100 / 1.1 = $1,000
- GST amount = $1,100 - $1,000 = $100
The GST-inclusive amount of $1,100 contains $100 of GST and $1,000 of ex-GST value.
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See the full comparison: best invoicing software for AU sole traders →
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FAQ
Common questions about the gst calculator australia
These are the practical questions operators usually run into when they apply the result to a real business decision.
When should I use add GST mode?
Use add GST when your starting amount is ex-GST and you want to see the GST amount and final GST-inclusive total.
When should I use remove GST mode?
Use remove GST when the amount already includes GST and you want to split it into the ex-GST amount and the GST component.
Does this calculator work for all tax situations?
No. It is only for the standard Australian 10% GST treatment and should not be relied on for special tax treatments or advice.
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