Consequences of Wrong HSN Codes & GST Rates

The authorities do not routinely overlook the filing of GST returns with a wrong HSN code. The consequences of wrong HSN codes can mean denied input tax credit, a ₹50,000 penalty, and in serious cases, a fraud notice from GST authorities. It usually begins with a miscoded invoice.

Key Takeaways

• A wrong or missing HSN code attracts a penalty up to ₹25,000 under Section 125 of the CGST Act, 2017 (₹50,000 combined when SGST is included).
• Charging an incorrect GST rate carries a penalty equal to 100% of the tax due or ₹10,000, whichever is higher.
• Incorrect HSN codes can trigger ITC disputes or denial, especially where invoice mismatches arise or Section 16 conditions are not satisfied.
• GSTR-1 amendment is the only prescribed correction method, subject to the 30th November deadline of the following year.

What is an HSN Code Under GST?

HSN stands for Harmonised System of Nomenclature, a globally standardised product classification system maintained by the World Customs Organization. Under GST, every goods invoice must carry a valid HSN code. Businesses with turnover up to ₹5 crore report 4-digit codes; above ₹5 crore, 6-digit codes are mandatory. Exporters and manufacturers generally use 8-digit codes.

The number of digits required in HSN reporting is not uniform and depends on turnover and applicable reporting rules. Generally, businesses with turnover up to ₹5 crore use 4-digit HSN codes, while those above ₹5 crore are required to report 6-digit codes. In certain cases - such as exports or specific notified categories - more detailed 8-digit classification may be used.

Use ClearTax's HSN Code Finder and GST Rate Tool to verify codes before invoicing.

Importance of Correct GST Rate Classification

The HSN code determines the applicable GST rate. A wrong HSN code under GST almost always produces a wrong rate on the invoice, although different classifications may sometimes fall under the same tax slab.

India runs standard GST slabs: 5%, 12%, 18%, and 28% along with a 0% rate for nil-rated goods. Certain supplies - such as exempt and zero-rated supplies, as well as notified special rate categories - fall outside these slabs. Many goods sit at chapter boundaries where a single sub-heading shifts the applicable rate entirely. The CBIC's advisory on HSN and GSTR-1 filing makes this clear: taxpayers are legally responsible for the HSN codes they report, even if the return was accepted without scrutiny. This is not a minor administrative concern. Over five financial years, India detected 91,370 GST evasion cases totalling ₹7.07 lakh crore, a significant portion of which involved ITC fraud tied to incorrect classification and invoice mismatches. Rate boundaries between chapters are where most of these misclassifications originate.

Common Reasons for Wrong HSN Codes and GST Rates

• Outdated code directories in billing software not updated after a rate revision
• Nearest-match code selection in multi-rate chapters like textiles or chemicals
• ERP mapping errors from setup, carried forward across hundreds of invoices
• Truncating 8-digit codes to 6 digits, which the GSTN advisory flags as invalid
• Copying codes from another business's invoice without verifying applicability

Consequences of Wrong HSN Codes

An HSN code mismatch GST filers report in GSTR-1 creates problems for both the supplier and the buyer.

When the supplier's GSTR-1 data does not match the invoice, buyers find discrepancies between GSTR-2A and GSTR-2B that block their ITC. Read ClearTax's Input Tax Credit under GST guide for eligibility conditions.

Consequences of Charging Wrong GST Rate

Incorrect GST rate consequences depend on whether the rate was too high or too low.

Charging a higher rate and retaining the excess without depositing it: penalty is 100% of the tax due or ₹10,000, whichever is higher. For unintentional overcharging, the buyer can demand a credit note and the excess must be refunded or adjusted. Charging a lower rate creates a shortfall that is a direct tax liability, payable with 18% annual interest from the original due date. Where the wrong GST rate charged appears deliberate, Section 122 of the CGST Act treats it as tax evasion, with a penalty equal to the full tax evaded.

If IGST is charged instead of CGST and SGST, no penalty applies. The correct tax must be paid and the wrongly deposited amount qualifies for a refund.

See ClearTax's Offences and Penalties under GST for the full penalty schedule.

Types of HSN Errors and Their Impact

• Clerical errors: Typo, missing digits, or wrong digit count. Usually correctable, but may trigger mismatch or scrutiny.
• Wrong HSN with same GST rate: Classification error without immediate rate difference, but still risky because it can cause reporting or customs issues.
• Wrong HSN causing undercharging: Leads to tax shortfall, interest, and possible demand.
• Wrong HSN causing overcharging: Creates excess tax collected, refund or credit note issues, and buyer disputes.
• Intentional misclassification: Higher risk of penalty, scrutiny, and possible fraud allegation.
• Customs-classification errors: Can delay imports/exports, trigger reassessment, or hold shipments.

How to Correct Wrong HSN Code or GST Rate

1. Amend GSTR-1 through the applicable amendment table within the prescribed deadline, or before filing GSTR-9, whichever is earlier
2. Pay differential tax in GSTR-3B for the month the error is identified, along with applicable interest
3. Issue a credit or debit note to the buyer and reflect it in GSTR-1 so their ITC is corrected
4. Update the HSN master in your billing software to prevent recurrence

A HSN code error in GST return that is not corrected in time compounds at the annual return stage. The penalty for wrong HSN code in GSTR-9 alone can reach ₹50,000 (combined CGST + SGST). See ClearTax's Mandatory HSN Code Reporting in GSTR-1 and GSTR-1A and How to File GSTR-1 on GST Portal.