Calculate GST in the Blink of an Eye - dummies

By Veechi Curtis, Lynley Averis

Part of Bookkeeping For Dummies Cheat Sheet (Australia/New Zealand Edition)

Even with a calculator close to hand, a few shortcuts to help you calculate Goods and Services Tax (GST) are real handy. The whole business of dividing by 11 or multiplying by 0.15 can get very ugly indeed.

Australia New Zealand
To calculate how much GST to add Multiply by 0.1 Multiply by 0.15
To add GST to arrive at a total price Multiply by 1.1 Multiply by 1.15
To calculate how much GST is included in a price Divide by 11 Multiply by 3 and then divide by 23
To calculate how much the price was before GST Divide by 1.1 Divide by 1.15