GST Classification & HSN/SAC Advisory

GST classification of goods and services for tax-rate and reporting purposes is governed by Section 9 (levy) read with the rate notifications issued under Section 11 of the CGST Act, 2017 (and the parallel notifications under the IGST Act, 2017), together with the mandatory HSN/SAC reporting requirement introduced by Notification No. 78/2020-Central Tax, dated 15 October 2020, read with Rule 46 of the CGST Rules, 2017.

Classification of goods uses the Harmonised System of Nomenclature (HSN), and classification of services uses the Services Accounting Code (SAC), both aligned to the customs tariff structure, to fix the applicable GST rate slab and any relevant exemption or concessional-rate notification.

Notification No. 78/2020-Central Tax mandates a minimum number of HSN/SAC digits on tax invoices and in Table 12 of FORM GSTR-1, calibrated to Aggregate Annual Turnover (AATO) in the preceding financial year:

• Taxpayers with AATO up to ₹5 crore must declare a minimum of 4 digits of the HSN/SAC code.


• Taxpayers with AATO exceeding ₹5 crore must declare a minimum of 6 digits.


• All export and import transactions require an 8-digit HSN code, irrespective of turnover, aligning with the Customs Tariff.

This requirement took effect from 1 April 2021, and GSTN subsequently rolled out mandatory portal-level validation of Table 12 of GSTR-1 in phases — Phase-1 from 1 April 2022, and Phase-2 (covering 6-digit reporting for the above-₹5-crore slab) from 1 November 2022 — progressively disallowing return filing where the mandated digit count is not met.

Misclassification carries direct compliance exposure: an incorrect HSN/SAC code can trigger application of the wrong rate slab, denial of a concessional notification, and mismatches that block or delay e-invoice and e-way bill generation, both of which draw on the declared HSN. Where the resulting short payment is identified, it is pursued through demand proceedings under Section 73 (non-fraud) or Section 74/74A (fraud or suppression) of the CGST Act. For advance, binding certainty on classification of a specific product or service before a transaction is undertaken, Section 97(2)(a) of the CGST Act provides the formal route via an application for advance ruling.

GST classification is the assignment of a supply to its correct HSN (for goods) or SAC (for services) code, which decides the rate of tax under the GST framework. The levy is under Section 9 of the CGST Act 2017 and the corresponding provisions of the IGST Act, and the rate is determined by the classification of the supply in the rate schedules notified under the Acts. Two similar supplies can sit one classification apart and carry materially different rates — and the classification must be consistent across the invoice, the returns and the e-invoicing.

The classification is where the GST rate is actually decided. A product filed under the wrong HSN pays the wrong rate — either the business over-pays and loses margin, or under-pays and builds a demand with interest. The services classification is the harder discipline: the composite and mixed supply rules of Section 8 of the CGST Act decide how a bundled supply is classified, and the principal-supply test is where most service classification disputes begin.

The cost of a wrong classification is the reversal with interest: a demand under Sections 73 or 74 computed on the turnover at the correct rate, less what was paid. The businesses that get the classification right run the rate correctly from the invoice; those that guess discover the difference at the audit.

This service is for businesses that want their classification right — products, services and the bundled supplies. We classify the supplies under the HSN and SAC codes and the rate schedules, apply the Section 8 composite and mixed supply rules, document the classification basis for the invoices and the returns, and where the position is genuinely uncertain, pursue the binding ruling under Section 97 of the CGST Act 2017.