The Harmonized System Nomenclature (HSN) Number is found on invoices in India. This number is used to identify the GST rates applied to goods and can be either a 4-, a 6-, or an 8-digit number. The HSN field can be a header field, a line-item field, or both. This field can be referenced on the printed invoice as HSN, SAC, or a combination of these names, such as HSN/SAC. Either way, the value is extracted to the HSN field. The system is used by customs authorities, statistical agencies, and other government bodies to monitor and regulate imports and exports.  

Each HSN code corresponds to a specific product category, organised in a hierarchical structure from broad categories to specific items. The first two digits represent the chapter, the next two digits are the heading, and the final two digits are the subheading. By standardising product classification, the HSN system simplifies customs procedures, ensures compliance with international trade regulations, and aids in the accurate collection of trade statistics. Businesses worldwide rely on HSN codes to ensure proper documentation and smooth cross-border transactions, promoting global trade efficiency and transparency.