Under CBIC Notification No. 78/2020-Central Tax (effective April 1, 2021), taxpayers with an aggregate turnover exceeding ₹5 Crore in the preceding financial year must report 6-digit HSN/SAC codes on all B2B and B2C tax invoices. Taxpayers with turnover up to ₹5 Crore must report a minimum of 4-digit HSN codes on B2B invoices, while HSN reporting on B2C invoices remains optional for them.
Statutory Background: Notification No. 78/2020-Central Tax & Rule 46
Harmonized System of Nomenclature (HSN) codes were developed by the World Customs Organization (WCO) to establish a uniform 8-digit international commodity classification system. Under Indian GST law, Section 31 of the CGST Act read with Rule 46 of the CGST Rules 2017 mandates that every tax invoice issued by a registered taxpayer must contain the correct HSN code for goods or Services Accounting Code (SAC) for services.
To streamline tax reporting and curb tax evasion via incorrect tariff classification, the Central Board of Indirect Taxes and Customs (CBIC) restructured HSN reporting requirements through Notification No. 78/2020-Central Tax and Notification No. 90/2020-Central Tax:
| Preceding FY Aggregate Turnover | Transaction Supply Type | Mandatory HSN / SAC Digits | Statutory Rule / Notification |
|---|---|---|---|
| Above ₹5.00 Crore | B2B (Registered Recipient) | 6 Digits Mandatory | Notification 78/2020-Central Tax |
| Above ₹5.00 Crore | B2C (Unregistered Recipient) | 6 Digits Mandatory | Notification 78/2020-Central Tax |
| Above ₹1.50 Cr up to ₹5.00 Cr | B2B (Registered Recipient) | 4 Digits Mandatory | Notification 78/2020-Central Tax |
| Above ₹1.50 Cr up to ₹5.00 Cr | B2C (Unregistered Recipient) | Optional (4 Digits Recommended) | Notification 78/2020-Central Tax |
| Up to ₹1.50 Crore | B2B & B2C Supplies | Optional (4 Digits Recommended) | Proviso to Rule 46 CGST Rules |
| Any Turnover Level | International Import / Export / SEZ | 8 Digits Mandatory | Notification 90/2020-CT & Customs Tariff Act |
8-Digit HSN Code Mandate for Specific Chemicals & Export/Import
While 6 digits represent the standard requirement for domestic transactions of large taxpayers, CBIC issued Notification No. 90/2020-Central Tax specifying 49 chemical items under Chapters 28, 29, 38, and 39 where taxpayers must report the full 8-digit HSN code regardless of turnover level.
Furthermore, under foreign trade regulations and Customs clearance procedures, all international import and export shipments, as well as supplies to Special Economic Zone (SEZ) units, require full 8-digit HSN classification matching Schedule I & II of the Customs Tariff Act 1975.
E-Invoicing Portal Validation & Table 12 GSTR-1 Summary Rules
Taxpayers generating e-invoices via the Invoice Registration Portal (IRP) must comply with strict automated validation checks. The IRP system rejects JSON uploads containing 2-digit or invalid 4-digit HSN codes for taxpayers with turnover > ₹5 Crore. Key operational rules include:
- GSTR-1 Table 12 Integration: Table 12 of Form GSTR-1 requires a consolidated HSN-wise summary of outward supplies including total quantity, total taxable value, and tax breakdown (CGST, SGST, IGST, Cess).
- Mandatory 6-Digit Validation: From May 2023, the GSTN portal enforces a strict 6-digit HSN check in GSTR-1 for businesses with turnover above ₹5 Crore. Entering a 4-digit code causes system warnings and potential filing blocks.
- Description Matching: The description entered in Table 12 must correspond accurately to the standard tariff description published in the CBIC HSN master database.
Consequences of Incorrect HSN Code Reporting: Penalties & ITC Risks
Failing to report mandatory HSN codes or using wrong digits leads to severe statutory liabilities:
- General Penalty under Section 125: Issuing tax invoices without mandatory details prescribed under Rule 46 constitutes an offense under Section 125 of the CGST Act, attracting a penalty of up to ₹25,000 under CGST and ₹25,000 under SGST (Total ₹50,000 per tax period).
- Recipient ITC Disallowance under Section 16(2)(a): Tax officers conducting statutory audits under Section 65 routinely disallow Input Tax Credit (ITC) to recipient buyers under Section 16(2)(a) if the supplier's tax invoice lacks mandatory 6-digit HSN codes, treating the invoice as non-compliant under Rule 46.
- Tax Rate Mismatch & Demand Notices: Quoting an HSN code associated with a 12% tax slab while collecting 18% (or vice versa) triggers automated discrepancy notices (Form DRC-01B) during GSTR-1 vs GSTR-3B reconciliation checks.
Worked Numerical Example: Multi-Product Billing & HSN Digit Determination
M/s Precision Tech Components Pvt Ltd operates in Gujarat with a preceding FY aggregate turnover of ₹8.50 Crore. During May 2026, the company issues two invoices:
Invoice #1: B2B Sale to Registered Buyer (M/s Apex Motors, Turnover ₹3 Cr)
- Product: Micro-controllers for automotive electronics (Chapter 85).
- Supplier Turnover: ₹8.50 Cr (> ₹5 Cr threshold) → Mandatory 6-Digit HSN required.
- Correct HSN Code: 853710 (Boards, panels, consoles for electric control).
- Invoice Value: Taxable Amount ₹5,00,000 + IGST @ 18% (₹90,000) = Total ₹5,90,000.
Invoice #2: B2B Sale of Chemical Formulations (Export to Dubai, UAE)
- Product: Organic solvent chemical (Chapter 29).
- Export Transaction → Mandatory 8-Digit HSN required.
- Correct HSN Code: 29023000 (Toluene).
- Invoice Value: $20,000 (Zero-rated export under LUT).
Summary Table for GSTR-1 Filing:
| HSN Code | Digits | Description | UQC | Total Qty | Taxable Value | IGST (₹) |
|---|---|---|---|---|---|---|
| 853710 | 6 Digits | Electric control panels/boards | NOS | 500 | ₹5,00,000 | ₹90,000 |
| 29023000 | 8 Digits | Toluene solvent export | KGS | 10,000 | ₹16,60,000 | ₹0 (LUT) |
Interactive HSN Lookup & Classification Tools
Verify mandatory HSN digits, tax rates, and tariff codes using our free HSN & SAC Code Finder. For comprehensive service tax rate lookups across Chapter 99, consult our SAC Code GST Rate Chart Guide. If you have encountered portal validation errors or tax rate discrepancies in GSTR-1, read our audit guide on Fixing GST HSN Code Mismatches & Penalties and calculate interest on delayed tax deposits with our GST Interest Calculator.
Compliance Action Plan for Tax Practitioners
- Audit Master Item Masters: Review ERP item masters to ensure all SKUs contain 6-digit HSN codes for businesses with turnover > ₹5 Crore.
- Cross-Check E-Way Bill & E-Invoice Data: Ensure HSN codes on e-way bills match e-invoice Schema 1.01 data exactly.
- Reconcile GSTR-1 Table 12: Reconcile HSN Summary values against Table 4 taxable values prior to monthly GSTR-1 submission.