HSN is the international system of codes for goods, maintained by the World Customs Organization and used by India for both customs and GST. The first two digits are the chapter, four digits the heading, six digits the sub-heading, and India adds two more for its eight-digit tariff. Ceramic tiles sit under heading 6907, brass rods under 7407, cotton T-shirts under 6109.
How many digits you must print
As of October 2026, the rule depends on your aggregate turnover in the previous financial year:
- Up to ₹5 crore: at least four digits on invoices to registered buyers. For sales to consumers it is optional.
- Above ₹5 crore: at least six digits on every invoice.
The same codes are summarised in Table 12 of GSTR-1, split between B2B and B2C sales.
Why the code matters
The HSN code decides the GST rate. Two items that look alike can sit under different headings at different rates, so the code is worth checking once when an item is created and then left alone. A wrong code repeated across a year of invoices is a common reason for notices.
In MatruOS each item carries its HSN code and GST rate, so every invoice line shows them without retyping.