This document provides a detailed advisory on the interest calculator feature within GSTR-3B. It includes an illustrative example showing how to input data and how the system computes interest for delayed payments. The advisory also explains a new 'Tax Liability Break-up (Voluntary)' button designed to help taxpayers accurately declare past liabilities and ensure correct interest calculation. This guide is useful for taxpayers who need to understand and manage interest liabilities in their GSTR-3B filings.