This document explains Rule 36(4) of the GST law, which limits the input tax credit (ITC) a business can claim based on invoices uploaded by suppliers. It details how the rule has evolved, including percentage changes and relief periods, and provides clear examples of ITC calculations and reconciliation. The guide is useful for registered persons needing to understand ITC eligibility and compliance with GST regulations, particularly concerning GSTR-2A and GSTR-2B.