How the GST calculator works
This GST calculator handles both directions. Enter your amount, choose whether it already includes GST or not, and the tool works out the net price, GST component, and gross total in one step.
To add GST: multiply the GST-exclusive amount by the rate (default 10%) to get the GST, then add it to get the gross. A $500 service becomes $550 once GST is added, with $50 in GST.
To remove GST: divide the GST-inclusive total by 1.1 (for 10%) to get the net. The GST is the difference between the two. A $550 invoice contains $50 in GST and $500 net.
The rate field defaults to 10% because that is the standard Australian rate, but you can adjust it if you are working with a different figure.
When to add vs remove GST
You add GST when you are quoting or invoicing a client. Your quoted price is GST-exclusive, so you add 10% on top and show both figures on the invoice.
You remove GST when you have a receipt or invoice total and need to split it into the net amount and the GST component, typically for a BAS, expense claim, or bookkeeping entry.
A few things worth knowing for Australian businesses:
- You only charge GST if your business is registered for GST (generally required once turnover hits $75,000/year).
- GST does not apply to all goods and services. Fresh food, most health and education services, and some exports are GST-free.
- Every tax invoice must show the GST amount, or say "Total price includes GST" when the GST is exactly one-eleventh of the total. If the sale is $1,000 or more, it must also show the buyer's identity or ABN.
- When in doubt, check with your accountant. This tool is a quick guide, not tax advice.
Stop calculating GST by hand
If you are sending invoices manually, GST errors are easy to make: wrong rate, wrong direction, or just a typo. Automation adds GST to invoices and quotes correctly every time, pulling the right figures from your job details without any manual maths.
Workvolve builds invoice and quoting automations for Australian small businesses. You get accurate GST on every document, sent automatically, with no copy-paste required. See our free invoice generator as a starting point, or read how to automate invoicing in Australia end to end.
If you want to take the manual work out of your invoicing completely, book a free 30-minute call and we will show you how it works.
