The document provides guidance on calculating output tax in Pakistan. It defines key terms related to sales tax such as taxable period, registered person, taxable activity, taxable and exempt goods. It explains how to calculate output tax for local supplies based on the value of supply, which considers discounted prices, consideration in kind, minimum production amounts. It also covers calculating output tax on imports based on customs value. The document outlines which input tax is adjustable, such as purchases supporting by invoices, and which transactions are not eligible like credit over 180 days or purchases of personal goods. It also specifies how tax liability is determined by subtracting input tax from output tax.