The calculation of Bank Nifty involves the establishment of a base date and value, which serve as foundational elements for the index. The base date, set as January 1st, 2000, signifies the initiation of tracking, while the base value, determined by NSE at Rs 1000, represents the index's worth on that commencement date. Notably, each bank in the index does not carry the same weight. Larger entities, such as HDFC Bank, hold a more substantial influence, while smaller entities, like IDFC Bank, have a comparatively lighter impact. This weightage is determined through the free-float market capitalisation method, wherein the size of each bank is a key factor in establishing its significance within the Bank Nifty framework.