Make sense of GST. Then get back to work.

How to calculate GST in Australia

Add 10% GST, remove GST from a total, and understand the divide-by-eleven rule with worked Australian dollar examples.

GST inclusive vs exclusive: which amount do you have?

Understand inc GST and ex GST labels, compare quotes fairly, and avoid adding GST twice.

GST-free and input-taxed sales: the practical difference

Learn why zero GST does not always mean GST-free, and how to handle mixed taxable and non-taxable invoice lines.

GST rounding: why a cent can differ

Understand rounding to cents, line-by-line calculations and the method used by CalcGST.

Invoicing

What should an Australian tax invoice include?

A practical tax invoice checklist, the $1,000 buyer identification rule, and a worked example.

Seven invoice mistakes worth checking before you send

Avoid adding GST twice, invalid quantities, missing buyer details and other common invoice errors.

How to make an invoice without GST

Create an ordinary invoice when not registered for GST, and understand why that differs from a GST-free tax invoice.

Quote, invoice or receipt: which document do you need?

Choose the right document for proposed work, payment requests and payments already received.

Running a business

The GST registration threshold in Australia

Understand the $75,000 business threshold, $150,000 non-profit threshold, and why turnover is not profit.

GST for sole traders: a practical starting point

Separate GST from income tax, understand registration, and organise quotes, invoices and purchase records.

Margin vs markup: calculate the right percentage

Use worked examples to distinguish profit margin from markup and keep GST out of like-for-like comparisons.

Using the tools

Calculate GST for a list of amounts

A step-by-step workflow for pasting multiple amounts, checking rounded totals and exporting a CSV.