If you have received a GST notice for HSN code mismatch between your invoice and GST return, you are not alone. The GST department's automated scrutiny system flags discrepancies when the HSN codes declared in GSTR-1 differ from those reported in GSTR-3B or e-invoices. This notice is issued under Section 61 of the CGST Act, 2017, and must be addressed within the stipulated timeframe to avoid penalties, demand orders, or registration suspension. Taxocity's compliance experts, with more than 3 decades of experience, help businesses draft watertight replies and prevent repeat notices.

• HSN mismatch notices are triggered by GSTN's automated matching engine comparing GSTR-1 data vs. GSTR-3B and e-invoice data
• Non-response within 30 days can lead to a best judgement assessment under Section 62
• Penalty for wrong HSN reporting can be up to Rs. 50,000 (Rs. 25,000 CGST + Rs. 25,000 SGST) per offence under Section 125

What is an HSN Code Mismatch in GST?

HSN stands for Harmonised System of Nomenclature. Under the GST regime, every supplier is required to report the correct HSN code against each supply made. The HSN code determines the applicable GST rate, input tax credit eligibility, and export benefit classification.

An HSN code mismatch occurs when the code declared on the tax invoice differs from the code reported in the GST return (GSTR-1, GSTR-3B) or the e-invoice data on the IRP (Invoice Registration Portal). The GSTN system automatically cross-validates these data points and generates a scrutiny notice when inconsistencies are detected.

Why Does the GST Department Issue This Notice?

The GST authority issues a notice for HSN code mismatch primarily to verify that:

• The correct GST rate has been applied on the supply
• Input tax credit (ITC) availed by the recipient is legitimate
• The supplier is not under-reporting tax liability by using a lower-rated HSN code
• Export or zero-rated benefits are not being claimed on non-eligible goods or services
• The e-invoice data and GSTR-1 data are consistent

The GSTN's data analytics and risk-profiling engine runs continuous reconciliation between GSTR-1, GSTR-3B, e-invoice records, and e-way bill data. Any mismatch triggers an automated flag, which is then converted into a formal notice by the proper officer.

Legal Provisions Governing HSN Mismatch Notices

Provision	Section / Rule	What it Covers
Scrutiny of Returns	Section 61, CGST Act	Proper officer can scrutinise returns and issue notice for discrepancies
HSN Reporting Requirement	Rule 46(a), CGST Rules	Mandatory HSN code on tax invoice based on turnover slab
General Penalty	Section 125, CGST Act	Penalty up to Rs. 50,000 for any contravention without specific penalty provision
Best Judgement Assessment	Section 62, CGST Act	If no response to notice, officer can assess tax based on available data
Demand and Recovery	Section 73 / 74, CGST Act	Demand for short-paid tax due to wrong HSN classification

HSN Code Reporting Requirements in 2026

The mandatory HSN digits required on invoices and returns depend on your aggregate annual turnover (AAT) in the preceding financial year:

Annual Turnover (PY)	HSN Digits on B2B Invoice	HSN Digits on B2C Invoice	HSN in GSTR-1
Up to Rs. 5 Crore	4 digits	Optional	4 digits
Above Rs. 5 Crore	6 digits	6 digits	6 digits
Exporters / E-invoice mandated	8 digits (recommended)	8 digits (recommended)	8 digits (recommended)

Note: Even if a 4-digit HSN is prescribed for your turnover slab, reporting a completely different 4-digit HSN (pointing to a different commodity class) constitutes a mismatch and can attract notice.

Common Causes of HSN Code Mismatch

• Manual data entry errors: Wrong HSN typed while preparing the invoice or filing GSTR-1
• Software configuration issues: ERP or billing software mapped to an incorrect HSN code at product master level
• Digit truncation: Using a 4-digit code in GSTR-1 while an 8-digit code appears on the e-invoice
• Rate change amendments: HSN codes reclassified by CBIC notifications, but the system was not updated
• Composite vs. mixed supply classification: Incorrect bundling of goods/services under a single HSN
• Amendment returns not filed: Invoices amended in a subsequent month but HSN correction not carried through in GSTR-1A or amendment tables
• E-invoice vs. GSTR-1 lag: Auto-populated data from IRP reflecting a different HSN than what was manually reported

How to Reply to a GST Notice for HSN Mismatch

Step 1: Identify the Exact Discrepancy

Download and compare your GSTR-1 summary, GSTR-3B, and the e-invoice data from the GST portal. Note each invoice where the HSN code differs and quantify the tax impact, if any.

Step 2: Determine the Correct HSN Code

Cross-check the correct HSN code as per the GST Rate Schedule (Notification No. 1/2017-Central Tax (Rate) for goods or Notification No. 11/2017-Central Tax (Rate) for services). If classification is disputed, refer to the Customs Tariff Act, 1975 for goods or SAC (Services Accounting Code) for services.

Step 3: Prepare Your Response

Draft a written reply addressing each discrepancy. Your reply should include:

• Reference to the notice number and date
• Acknowledgement of the specific invoices flagged
• Explanation for the mismatch (typographical error, software issue, genuine reclassification, etc.)
• Supporting documents: tax invoices, product catalogue, HSN classification rationale
• Declaration that no revenue loss has occurred due to the mismatch (if applicable)

Step 4: File Amendment Returns if Required

If the mismatch arose due to a reporting error, file an amendment in the next GSTR-1 (Table 9A/9B for B2B amendments). Attach proof of the amendment when submitting your reply. If the error has caused a short-payment of tax, voluntarily pay the differential tax along with applicable interest under Section 50 before replying to the notice. This demonstrates good faith and significantly reduces the risk of penalty.

Step 5: Submit Reply on GST Portal

Log in to the GST portal, navigate to Services > User Services > View Notices and Orders, locate the relevant notice, and submit your reply along with supporting documents before the due date.

Consequences of Ignoring the Notice

Failing to respond to a GST scrutiny notice for HSN mismatch can have serious consequences:

• Best judgement assessment (Section 62): The officer assesses your tax liability based on available information, which is often unfavourable
• Demand with interest: Differential tax (if any) is demanded along with 18% per annum interest under Section 50
• Penalty under Section 125: Up to Rs. 50,000 per offence for incorrect HSN reporting
• ITC reversal for recipients: Your buyers who availed ITC based on the wrong HSN may face demand notices
• Escalation to Section 73/74: Repeated non-compliance can lead to a show cause notice for tax evasion, especially under Section 74 (with intent)
• Suspension or cancellation of GST registration

HSN Mismatch vs. Other GST Discrepancy Notices

Notice Type	Triggering Discrepancy	Governing Section	Key Risk
HSN Code Mismatch	HSN on invoice ≠ HSN in GSTR-1/3B	Section 61	Wrong rate applied, ITC eligibility
Outward Supply vs. E-way Bill Mismatch	GSTR-1 turnover ≠ E-way bill data	Section 61	Suppression of outward supply
Scrutiny Notice for Return Discrepancy	GSTR-1 vs. GSTR-3B mismatch	Section 61	Tax short-payment
E-Invoice Non-Generation	No IRN for eligible invoices	Rule 48(4)	Invoice invalidity, ITC denial to buyer
GST Audit Notice (ADT-01)	Department audit trigger	Section 65	Comprehensive books examination

How to Prevent HSN Code Mismatch Notices

• Conduct a periodic HSN code audit of your product/service master in your billing or ERP software
• Reconcile GSTR-1 data with e-invoice data every month before finalising returns
• Update your HSN codes promptly when CBIC issues rate change notifications
• Use the GST filing reconciliation dashboard to spot mismatches before the return is filed
• Train your accounts team on the correct digit-level HSN reporting requirement based on your turnover slab
• For businesses with composite or mixed supplies, get a formal HSN classification opinion from a GST expert

How Taxocity Helps You Resolve HSN Mismatch Notices

Taxocity has been supporting Indian businesses with end-to-end GST compliance for over 3 decades. With a trust rating of 4.8/5 from more than 5,000 clients, our team of real human GST experts handles everything from notice analysis to final resolution:

• Notice Review: We analyse the exact invoices and returns flagged, identify the root cause, and quantify the tax impact within 24 hours
• Reply Drafting: Our experts draft a precise, legally sound reply supported by the relevant sections of the CGST Act and CBIC notifications
• Amendment Returns: We file required amendments in GSTR-1 and coordinate any differential tax payment with interest calculation
• Future Prevention: We set up a monthly reconciliation process to ensure your HSN codes are always consistent across invoices, e-invoices, and returns
• 100% Compliance Guarantee: We stand behind every filing and reply we submit on your behalf

Whether you are a small trader or a large enterprise, our GST filing and compliance services are structured to give you complete peace of mind. From the moment a notice arrives to the final closure order, Taxocity is with you at every step.

Key Takeaways

1. A GST notice for HSN code mismatch is issued under Section 61 of the CGST Act when the HSN code on your invoice does not match the code reported in GSTR-1, GSTR-3B, or e-invoice data.
2. Businesses with turnover up to Rs. 5 crore must report 4-digit HSN; above Rs. 5 crore, 6-digit HSN is mandatory in 2026.
3. Respond within the stipulated time (usually 30 days) to avoid best judgement assessment under Section 62.
4. If a genuine error occurred, file GSTR-1 amendments and pay differential tax with interest proactively.
5. Non-response can attract a penalty of up to Rs. 50,000 and escalate to a demand under Section 73 or 74.
6. Regular HSN reconciliation between invoices, GSTR-1, and e-invoice data is the best preventive measure.

Frequently Asked Questions

Can a wrong HSN code lead to ITC reversal for my buyer?

Yes. If the GST department determines that the HSN code mismatch resulted in an incorrect tax rate being applied, ITC availed by your buyer based on that invoice may be reversed or denied under Rule 86A or Section 17(5).

Is HSN code mismatch a criminal offence?

A simple typographical or software error in HSN reporting is generally treated as a technical lapse and is addressed through civil proceedings (penalty and demand). However, if the mismatch is found to be deliberate and results in systematic under-payment of tax, it can be treated as fraud under Section 74, which carries higher penalties and can potentially attract prosecution under Section 132.

What if I disagree with the HSN classification suggested by the officer?

You have the right to present your classification rationale in your reply, citing the relevant GST rate notification, the Customs Tariff Act, 1975 (for goods), or SAC descriptions (for services). If the officer still issues a demand order, you can appeal to the Appellate Authority under Section 107 of the CGST Act.

Can Taxocity help me if the notice has already been escalated to a demand order?

Yes. Taxocity provides end-to-end GST compliance support, including representation before the Appellate Authority and assistance with rectification applications. Contact our experts for an immediate consultation.

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Disclaimer: This article is for general informational purposes only and does not constitute tax or legal advice. GST laws and notifications are subject to change. Please consult a qualified tax advisor or GST practitioner before taking any action based on the information provided here.