About GST & Sales Tax Calculator

GST & Sales Tax Calculator is a free calculator for adding or removing Australian GST (10%) and working out US sales tax for every state. It is completely free to use, works on any phone, tablet or computer, and does all of its calculations instantly in your browser — nothing you type is sent to a server.

The tool was built for people in the United States and Australia, and everything on this site is written with both countries in mind.

Why we built it

Most tools like this are cluttered, slow, or hide the answer behind pop-ups. We wanted something that loads fast, gives the answer straight away, and explains the details underneath for anyone who wants them.

Get in touch

Spotted a mistake, or have an idea for an improvement? We read every message — see the contact page.