With effect from 1 April 2021, the Government has made it mandatory for GST taxpayers to mention Harmonised System of Nomenclature (HSN) codes for goods and Service Accounting Codes (SAC) for services on tax invoices, in line with revised turnover-based thresholds. Taxpayers having an aggregate turnover of more than ₹5 crore in the preceding financial year are now required to mention 6-digit HSN/SAC codes on all invoices for taxable supplies, while those with turnover up to ₹5 crore must mandatorily furnish 4-digit HSN codes on B2B invoices. This marks a tightening of requirements compared to the earlier norm, which prescribed 4-digit and 2-digit codes respectively. The change is aimed at improving uniformity in classification, reducing ambiguity in tax rates, and strengthening data quality under the GST system. The press release clarifies that 6-digit HSN codes are internationally standardised and common across Customs and GST, with GST relying on the Customs Tariff classification framework. Detailed HSN codes, GST rate schedules, and reference tools are available on the CBIC and GST portals, including an online HSN search facility. The release also notes that many manufacturers, importers, exporters, and traders are already familiar with and using HSN codes, including at higher digit levels, even prior to GST. Overall, the measure is intended to promote consistency, facilitate better compliance and analytics, and align GST documentation more closely with global classification standards.