Introduction

If you are a registered business owner under the Goods and Services Tax (GST) regime, the term "GSTR-1" is likely a monthly or quarterly fixture in your calendar. Often called the "sales return," GSTR-1 is the foundation of the entire GST filing system. It is where you report every invoice you have issued, every credit note you have generated, and every item you have sold.

Why is this form so critical? Because the data you enter in your GSTR-1 determines the Input Tax Credit (ITC) available to your buyers. If you miss a deadline or make an error, your customers cannot claim their credit, which can strain business relationships and lead to strict penalties from the tax department.

We will break down everything you need to know about GSTR-1, from the latest 2025 updates regarding HSN codes to a detailed look at late fees, eligibility, and a step-by-step filing walkthrough.

Table of Contents

1. What is GSTR-1?
2. Eligibility: Who Needs to File GSTR-1?
3. Due Dates: Monthly vs. Quarterly (QRMP)
4. Key Components: What Details Must Be Filed?
5. Updated HSN Code Rules for 2025
6. Step-by-Step Guide to File GSTR-1 Online
7. Late Fees and Penalties
8. Can You Revise GSTR-1?
9. FAQs

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What is GSTR-1?

Form GSTR-1 is a monthly or quarterly statement of Outward Supplies (sales) that must be furnished by all normal and casual registered taxpayers.

It is important to understand that GSTR-1 is not a tax payment return. It is purely a reporting return. You do not pay tax when filing GSTR-1; you simply tell the government, "Here is what I sold, and here is the tax liability I have collected." The actual tax payment happens when you file GSTR-3B.

However, GSTR-1 is the source of truth. The liability you declare here auto-populates into your GSTR-3B, and the invoices you upload here reflect in your buyer's GSTR-2A/2B, allowing them to claim Input Tax Credit.

Eligibility: Who Needs to File GSTR-1?

Almost every business registered under GST must file GSTR-1. Whether you had zero sales or transactions worth crores, filing is mandatory.

Who Must File:

• Every registered dealer has a valid GSTIN.
• Casual Taxable Persons (CTP).

Who is Exempt from GSTR-1?

The following categories of registered persons are NOT required to file GSTR-1 (they have specific forms of their own):

1. Composition Dealers: They file CMP-08 and GSTR-4.
2. Input Service Distributors (ISD): They file GSTR-6.
3. Non-Resident Taxable Persons: They file GSTR-5.
4. TCS Collectors (E-commerce operators): They file GSTR-8.
5. TDS Deductors: They file GSTR-7.
6. OIDAR Service Providers: They file GSTR-5A.

Due Dates: Monthly vs. Quarterly (QRMP)

The due date depends on your aggregate annual turnover and whether you have opted for the QRMP (Quarterly Return Monthly Payment) scheme.

1. Monthly Filers

• Who: Businesses with an annual turnover exceeding ₹5 Crore, or those with a lower turnover who have not opted for the QRMP scheme.
• Due Date: The 11th of the following month.

Example: Return for November 2025 is due on December 11, 2025.

2. Quarterly Filers (QRMP Scheme)

• Who: Businesses with a turnover up to ₹5 Crore that have opted into the scheme.
• Due Date: The 13th of the month following the end of the quarter.

Example: For the quarter October–December 2025, the due date is January 13, 2026.

Note on IFF (Invoice Furnishing Facility):

Quarterly filers have the option to upload invoices for the first two months of the quarter using the IFF facility (by the 13th of the next month) so that their buyers can claim credit immediately, rather than waiting for the quarter to end.

Key Components: What Details Must Be Filed?

When you open GSTR-1 on the portal, you will see various "Tiles" or tables. Here is what goes into each:

• Table 4A, 4B, 6B, 6C (B2B Invoices): Details of supplies made to other registered businesses. You must enter the GSTIN of the buyer, invoice number, date, value, and tax rate.
• Table 5 (B2C Large): Inter-state supplies (selling to a different state) made to unregistered persons (consumers) where the invoice value is more than ₹2.5 Lakh.
• Table 7 (B2C Others): This is for all other sales to consumers (unregistered). You do not need invoice-level details here; just the total value of sales consolidated by State (Place of Supply) and Tax Rate.
• Table 6 (Exports): Supplies exported out of India, deemed exports, or sales to SEZ units.
• Table 9B (Credit/Debit Notes): If you issued a credit note (sales return) or debit note to a registered dealer, report it here.
• Table 12 (HSN-wise Summary): A summary of items sold, classified by HSN code (more on this below).
• Table 13 (Documents Issued): A summary of the total number of invoices, credit notes, and challans issued during the period.

Updated HSN Code Rules for 2025

As of late 2024 and moving into 2025, the government has tightened the rules regarding Table 12 (HSN Summary). You can no longer ignore this section or enter generic data.

1. Mandatory Reporting: Reporting the HSN (Harmonized System of Nomenclature) code is mandatory for all taxpayers.

2. Turnover Limits:

   1. Turnover > ₹5 Crore: You must report a 6-digit HSN code.
   2. Turnover < ₹5 Crore: You must report a 4-digit HSN code.

3. Validation: The GST portal now validates these codes against the master list. If you enter an invalid HSN or a description that doesn't match the official HSN master, the system may flag a warning or error, preventing filing.

Step-by-Step Guide to File GSTR-1 Online

Filing GSTR-1 is a logical process. Follow these steps to ensure accuracy.

Step 1: Log in to the GST Portal

Go to the official GST website and log in using your Username and Password.

Step 2: Navigate to Returns Dashboard

Click on Services > Returns > Returns Dashboard. Select the Financial Year and the specific Month/Quarter you are filing for. Click "Search."

Step 3: Select GSTR-1

You will see the GSTR-1 tile. Click on "Prepare Online." (If you have a large volume of invoices, you may use the "Prepare Offline" tool, but for most SMEs, online is sufficient.

Step 4: Enter Invoice Details

• B2B Invoices: Click on the B2B tile. Click "Add Details." Enter the Buyer's GSTIN. The name will auto-populate. Enter invoice number, date, and taxable value. The system calculates the tax automatically. Save the record.
• B2C Others: For daily sales to consumers, enter the aggregate value for each tax rate (e.g., Total sales at 18%, Total sales at 12%).

Step 5: Fill HSN and Document Summary

Do not skip Table 12 (HSN) and Table 13 (Docs). These are mandatory. Ensure the number of invoices in Table 13 matches the actual invoices uploaded.

Step 6: Generate Summary

Once all data is entered, click the "Generate GSTR-1 Summary" button at the bottom. Wait for a minute and refresh the page until the status shows "Generated."

Step 7: Preview and Submit

Review the summary tiles to ensure the total Liability matches your internal books. Click the checkbox to confirm the declaration and click "Submit."

Warning: Once you click Submit, the data is frozen and cannot be changed for this month.

Step 8: File Return

After submission, the "File Return" button will become enabled. Click it, select your authorized signatory, and file using EVC (OTP on mobile) or DSC (Digital Signature, mandatory for Companies/LLPs).

Late Fees and Penalties

Filing GSTR-1 late attracts a "Late Fee." Unlike interest (which applies to late tax payment), late fees apply purely for the delay in filing the return.

The late fees are charged separately for CGST and SGST.

Scenario

Late Fee (Per Day)

Maximum Cap (Turnover < ₹1.5 Cr)

Maximum Cap (Turnover ₹1.5 Cr - ₹5 Cr)

Maximum Cap (Turnover > ₹5 Cr)

Nil Return

₹20 (₹10 CGST + ₹10 SGST)

₹500

₹500

₹500

Normal Return

₹50 (₹25 CGST + ₹25 SGST)

₹2,000

₹5,000

₹10,000

Note: These caps are based on rationalized late fee notifications. If you delay significantly, the portal will auto-calculate this fee, and you must pay it in the next month's GSTR-3B filing.

Additional Consequences of Non-Filing:

• Blocking of E-Way Bill: If you fail to file GSTR-1 for two consecutive periods, you cannot generate E-Way Bills.
• Blocking of GSTR-1: Under Rule 59(6), if you have not filed GSTR-3B for the previous month, you may be blocked from filing the current month's GSTR-1.

Can You Revise GSTR-1?

A common question is, "I made a mistake in GSTR-1; can I revise it?"

The short answer is no. The GST system does not allow you to revise a return once it is filed.

However, you can amend the details in the subsequent month's GSTR-1.

Example: If you entered an invoice incorrectly in November's GSTR-1, you can go to the "Amendment of B2B Invoices" table in December's GSTR-1 and correct the original invoice details.