The GST that a business collects from customers is called output tax. Conversely, GST paid on a business’s purchases or paid to its suppliers is called its input tax. A GST-registered business can claim credit for its GST input tax. Furthermore, input tax can offset output tax. Therefore, GST-registered companies only pay GST on the amount of “value added” to their products or services, which is calculated as the difference between their output and input tax.