HSN code under GST: what it is, how many digits, and how to find yours

HSN stands for Harmonised System of Nomenclature, the goods classification maintained by the World Customs Organization and used by more than 200 countries. The first six digits are international; India adds two more for its customs tariff. GST borrows the same codes, and the GST rate notifications are written against them.

Services use the Services Accounting Code instead: six digits beginning with 99, such as 9982 for legal and accounting services and 9983 for other professional and technical services.

Since the tax periods of 2025, Table 12 of GSTR-1 is split into separate B2B and B2C tabs, the HSN is chosen from a dropdown rather than typed, and the portal checks the Table 12 values against the invoices reported elsewhere in the return. A code that is not in the HSN master cannot be entered at all, which is how old or mistyped codes in billing software surface as a filing failure on the 11th.

1. Start from what the product is and what it is made of, not from what a competitor uses. Classification follows the rules of interpretation of the tariff: the most specific description wins, and mixed goods follow their essential character.
2. On the GST portal, use Services, User Services, Search HSN Code, by description or by number; it lists the matching headings and lets you download the master.
3. Confirm the rate on the CBIC GST rate finder or the rate notification for that heading. Since the rate rationalisation of 22 September 2025, most goods sit at 5 or 18 percent, with a 40 percent rate for a short list of sin and luxury goods, so a wrong heading now more often means a wrong rate.
4. Cross-check with your supplier’s invoice, the customs bill of entry if you import, and the advance rulings for your product where one exists.
5. Record the reasoning in a classification note. It is the first thing an officer asks for.

If the wrong code carries a lower rate, the difference is a short payment of tax, recoverable with interest at 18 percent and a penalty; for FY 2024-25 onwards the notice can issue up to 42 months after the annual return due date, with or without suppression. If it carries a higher rate, you have overcharged customers and the refund route is slow. Either way, the e-invoice and e-way bill carry the same code, so one error repeats across every document. A missing or wrong HSN on invoices attracts a general penalty of up to ₹25,000 under each of the central and state Acts, and recurring mismatches in Table 12 draw scrutiny notices.

Where a product genuinely sits between two headings with different rates, an advance ruling is the clean answer; it binds the department for your transaction. Our registration service sets the HSN and SAC codes at the outset, and notice replies handle classification disputes.