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.
|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|