GSTR-1 FILING
What is GSTR-1? A Complete Introduction
GSTR-1 is a monthly or quarterly GST return that every registered taxpayer in India is required to file under the Goods and Services Tax (GST) regime. It contains details of all outward supplies (sales) made by the taxpayer during the return period. Simply put, GSTR-1 is your official declaration to the government about everything you have sold — to businesses and consumers alike.
Introduced with the GST Act in July 2017, GSTR-1 is one of the most critical returns under the Indian tax system. It forms the foundation of the GST compliance ecosystem because the data you file in GSTR-1 directly impacts your buyer’s ability to claim Input Tax Credit (ITC). An error in your GSTR-1 could mean your customer loses their rightful ITC — so accuracy and timeliness are paramount.
Who Must File GSTR-1?
The following registered taxpayers are mandatorily required to file GSTR-1:
- Regular taxpayers registered under GST (including those with turnover above Rs. 5 crore)
- Taxpayers filing quarterly returns under QRMP (Quarterly Return Monthly Payment) scheme
- SEZ (Special Economic Zone) units and developers
- Casual taxable persons
- Non-resident taxable persons (in modified form)
The following categories are EXEMPT from filing GSTR-1:
- Composition scheme dealers (they file CMP-08 and GSTR-4)
- Input Service Distributors (ISD)
- Non-resident foreign taxpayers
- OIDAR service providers filing GSTR-5A
- TDS deductors and TCS collectors (they file GSTR-7 and GSTR-8)
GSTR-1 Due Dates: Monthly & Quarterly
The due dates for GSTR-1 filing depend on the taxpayer’s annual aggregate turnover and whether they have opted for the QRMP scheme. Let us break it down clearly:
Monthly GSTR-1 Filers
Taxpayers with aggregate annual turnover exceeding Rs. 5 crore must file GSTR-1 every month. The due date is the 11th of the following month.
Return Period | Due Date | Applicable Turnover |
April 2025 | 11th May 2025 | Above Rs. 5 Crore |
May 2025 | 11th June 2025 | Above Rs. 5 Crore |
June 2025 | 11th July 2025 | Above Rs. 5 Crore |
July 2025 | 11th August 2025 | Above Rs. 5 Crore |
August 2025 | 11th September 2025 | Above Rs. 5 Crore |
September 2025 | 11th October 2025 | Above Rs. 5 Crore |
October 2025 | 11th November 2025 | Above Rs. 5 Crore |
November 2025 | 11th December 2025 | Above Rs. 5 Crore |
December 2025 | 11th January 2026 | Above Rs. 5 Crore |
January 2026 | 11th February 2026 | Above Rs. 5 Crore |
February 2026 | 11th March 2026 | Above Rs. 5 Crore |
March 2026 | 11th April 2026 | Above Rs. 5 Crore |
Quarterly GSTR-1 Filers (QRMP Scheme)
Taxpayers with aggregate annual turnover up to Rs. 5 crore who have opted for the QRMP scheme file GSTR-1 quarterly. The due date is the 13th of the month following the quarter end.
Quarter | Period | Due Date |
Q1 | April – June 2025 | 13th July 2025 |
Q2 | July – September 2025 | 13th October 2025 |
Q3 | October – December 2025 | 13th January 2026 |
Q4 | January – March 2026 | 13th April 2026 |
Important: Taxpayers under QRMP can also use the Invoice Furnishing Facility (IFF) to upload B2B invoices for Month 1 and Month 2 of a quarter (on or before 13th of the next month), enabling their buyers to claim ITC without waiting for the quarterly GSTR-1. |
What Happens If You Miss the Due Date?
Missing the GSTR-1 due date results in the following consequences:
- Late Fee: Rs. 50 per day (Rs. 25 CGST + Rs. 25 SGST) for returns with tax liability. For NIL returns, the late fee is Rs. 20 per day (Rs. 10 CGST + Rs. 10 SGST).
- Maximum Late Fee Cap: Rs. 10,000 per return (Rs. 5,000 CGST + Rs. 5,000 SGST). For small taxpayers with turnover up to Rs. 1.5 crore, this is further capped.
- Blocking of GSTR-3B: If GSTR-1 is not filed for two consecutive months, the taxpayer cannot file GSTR-3B either, freezing their ITC claims.
- Impact on Recipients: Your buyers will not be able to see your invoices in their GSTR-2B, affecting their ITC.
GSTR-1 Format: All Tables Explained in Detail
The GSTR-1 return consists of 13 tables, each capturing a specific category of outward supply. Understanding each table is critical for accurate filing. Here is a comprehensive breakdown:
Table 1, 2 & 3: Basic Details
Table | Field | Description |
Table 1 | GSTIN | Your 15-digit GST Identification Number |
Table 2 | Legal Name / Trade Name | Auto-populated from GST registration |
Table 3 | Aggregate Turnover | Turnover in preceding financial year & April–June of current FY |
Table 4: B2B Supplies (Taxable)
Table 4 captures all taxable outward supplies made to registered businesses (B2B). This includes:
- Invoice number, date, and value
- GSTIN of the recipient
- Place of supply
- Taxable value and applicable tax rates (IGST / CGST / SGST / Cess)
- Whether supply is eligible for reverse charge
This table is critical because it directly feeds into your buyer’s GSTR-2B for ITC claims. Every invoice reported here must be accurate.
Table 5: B2C Large Supplies (Interstate)
This table covers inter-state supplies made to unregistered persons (consumers) where the invoice value exceeds Rs. 2.5 lakh. Key fields include state-wise breakup and invoice-level details.
Table 6: Export Supplies
Sub-Table | Type |
6A | Exports with payment of IGST (WPAY) |
6B | Exports without payment of IGST (WOPAY) |
Export details include shipping bill number, date, port code, foreign currency, and invoice details. This is critical for claiming refunds under GST.
Table 7: B2C Small & Other Supplies
This consolidated table captures:
- Intra-state and inter-state B2C sales below Rs. 2.5 lakh
- State-wise summary of supplies to unregistered persons
- Tax rate-wise breakup (5%, 12%, 18%, 28%)
Table 8: Nil Rated, Exempt & Non-GST Supplies
Category | Meaning |
Nil Rated | Supplies attracting 0% GST (e.g., grains, milk) |
Exempt | Supplies exempted from GST (e.g., certain financial services) |
Non-GST | Supplies outside GST scope (e.g., alcohol, petroleum) |
Table 9: Amendments to B2B Supplies (Previous Period)
Table 9A allows you to amend or correct B2B invoices reported in previous tax periods. The original invoice details and amended details must both be provided. This is essential for rectifying errors discovered after filing.
Table 10 & 11: Amendments to B2C Supplies
- Table 10: Amendments to B2C Large supplies (previously reported in Table 5)
- Table 11: Amendments to B2C Small and other supplies
Table 12: HSN-Wise Summary of Outward Supplies
Table 12 requires a summary of outward supplies categorized by HSN (Harmonized System of Nomenclature) code. This is mandatory based on turnover:
Annual Turnover | HSN Digit Requirement |
Up to Rs. 1.5 Crore | Optional (but recommended) |
Rs. 1.5 Crore to Rs. 5 Crore | 2-digit HSN code mandatory |
Above Rs. 5 Crore | 4-digit or 6-digit HSN code mandatory |
Table 13: Documents Issued Summary
Table 13 captures a summary of all documents issued during the tax period, including:
- Tax invoices (original and revised)
- Debit notes and credit notes
- Delivery challans, receipt vouchers, payment vouchers, and refund vouchers
- Serial number ranges for each document type
How to File GSTR-1: Step-by-Step Guide
Filing GSTR-1 on the GST portal is a straightforward process once you understand the steps. Here is a complete walkthrough:
Pre-Filing Checklist
- Your GSTIN and login credentials for the GST portal (www.gst.gov.in)
- Sales register / invoice data for the return period
- HSN codes for goods/services supplied
- Details of export invoices (if applicable)
- EVC (Electronic Verification Code) or DSC (Digital Signature Certificate) for signing
Step-by-Step GSTR-1 Filing Process
Step 1: Login to the GST Portal
Visit www.gst.gov.in. Click on ‘Login’ and enter your username and password. Complete CAPTCHA verification and log in to your GST account dashboard.
Step 2: Navigate to Returns Dashboard
Go to: Services > Returns > Returns Dashboard. Select the Financial Year and Return Filing Period (month/quarter). Click ‘Search’ to see your pending returns.
Step 3: Open GSTR-1 Form
Click on ‘Prepare Online’ under GSTR-1. This opens the GSTR-1 dashboard where you can see all 13 tables ready for data entry.
Step 4: Enter Invoice Data
You have two methods to enter invoice data:
- Manual Entry: Click on individual tables (4, 5, 6, 7 etc.) and enter invoice details one by one. This is suitable for businesses with low invoice volumes.
- JSON Upload: Prepare invoice data in the GSTN-prescribed JSON format using GST-compatible accounting software (Tally, Zoho Books, ClearTax, etc.) and upload the file directly. Recommended for businesses with high invoice volumes.
Step 5: Add B2B Invoices (Table 4)
For each B2B invoice, enter: GSTIN of buyer, invoice number, invoice date, invoice value, place of supply, taxable value, and applicable tax amounts (IGST or CGST/SGST). Reverse charge applicability must also be indicated.
Step 6: Add B2C Supplies (Tables 5 & 7)
For B2C supplies above Rs. 2.5 lakh (interstate), provide invoice-level details in Table 5. For all other B2C supplies (intra-state and inter-state below Rs. 2.5 lakh), provide the consolidated state-wise, rate-wise summary in Table 7.
Step 7: Enter Export Details (Table 6)
For export supplies, select whether with payment of tax or without payment of tax. Enter shipping bill number, date, port code, and invoice details. Link invoices with shipping bills for refund claims.
Step 8: Fill HSN Summary (Table 12)
Enter the HSN/SAC code-wise summary of goods/services supplied. Include total quantity, taxable value, and tax amount for each HSN code. Ensure HSN digit accuracy as per your turnover bracket.
Step 9: Save and Preview
Click ‘Save GSTR-1’ after entering all data. Generate a ‘Preview’ of the return to review all entries. Check for any errors or mismatches. The system will highlight errors that need correction before submission.
Step 10: Submit and File
Once satisfied with the data, click ‘Submit’ to freeze the GSTR-1 data. After submission, file the return using:
- EVC (OTP on registered mobile number) for individuals and proprietors
- DSC (Digital Signature Certificate) for companies and LLPs
After successful filing, an Acknowledgment Reference Number (ARN) is generated. Save this for your records.
Invoice Furnishing Facility (IFF) for QRMP Taxpayers
Under the QRMP scheme, quarterly filers can use the Invoice Furnishing Facility (IFF) to upload B2B invoices for the first two months of a quarter (without filing a full GSTR-1). This allows their buyers to see invoices in GSTR-2B and claim ITC on a monthly basis.
Month | IFF Availability | Due Date |
Month 1 of Quarter | Optional — B2B invoices only | 13th of Month 2 |
Month 2 of Quarter | Optional — B2B invoices only | 13th of Month 3 |
Month 3 of Quarter | Mandatory GSTR-1 for all supplies | 13th of Month following quarter |
Note: IFF is optional. If you do not use IFF for the first two months, all invoices for the full quarter must be reported in the quarterly GSTR-1. |
Common GSTR-1 Errors and How to Avoid Them
Common Error | Impact | How to Avoid |
Wrong GSTIN of recipient | Buyer loses ITC; mismatch in GSTR-2B | Verify GSTIN on GST portal before invoice |
Incorrect HSN code | Discrepancy in HSN summary report | Refer to HSN master list; validate with CA |
Wrong place of supply | Incorrect IGST/CGST-SGST bifurcation | Check POS rules under IGST Act carefully |
Missing credit/debit notes | Buyer ITC overstated or understated | Report all CDNs in Tables 9B/9C |
Invoice value mismatch | GST liability mismatch in GSTR-3B | Reconcile with books before filing |
Filing after due date | Late fee applicable; GSTR-3B blocked | Set calendar reminders; use auto-reminder tools |
Duplicate invoice entry | Inflated tax liability; reconciliation issues | Ensure unique invoice numbers; use accounting software |
How to Amend GSTR-1 After Filing
Once GSTR-1 is filed, it cannot be directly edited. However, the GST law allows amendments through specific tables in the NEXT month’s or quarter’s GSTR-1:
- Amend B2B invoices: Use Table 9A of the subsequent GSTR-1
- Amend B2C Large invoices: Use Table 10 of the subsequent GSTR-1
- Add missed invoices: Report them in the relevant tables of the next return period
GSTR-1 vs GSTR-3B: Key Differences
Aspect | GSTR-1 | GSTR-3B |
Purpose | Report outward supplies (sales) | Declare tax liability and pay GST |
Due Date (Monthly) | 11th of next month | 20th of next month |
Tax Payment | No tax payment | Tax is paid here |
Amendments | Via next period’s GSTR-1 | Via subsequent GSTR-3B |
Data Source | Invoice-level data | Summary/consolidated data |
Impact on Buyer | Feeds GSTR-2B for ITC | Taxpayer’s own liability |
Pro Tips for Error-Free GSTR-1 Filing
- Reconcile before filing: Always reconcile your sales register with GSTR-1 data before submission. Match invoice counts, taxable value, and tax amounts.
- Verify buyer GSTINs: Use the GSTN search tool to validate your customers’ GSTINs before raising invoices. Invalid GSTINs will cause mismatches in GSTR-2B.
- Use GST-compliant accounting software: Tools like Tally Prime, Zoho Books, ClearTax, or HostBooks auto-generate GSTR-1 JSON files, minimizing manual errors.
- File IFF on time (QRMP filers): Upload B2B invoices via IFF by the 13th of each month to ensure your B2B customers can claim ITC timely.
- Check GSTR-2B before filing GSTR-3B: While not directly linked to GSTR-1 filing, this habit ensures your supply chain is clean.
- Maintain backup of ARNs: Always save the Acknowledgment Reference Numbers of all filed returns for future reference, audits, or disputes.
- Set advance reminders: Use Google Calendar or accounting software reminders at least 3-5 days before due dates to avoid last-minute rush and portal slowdowns.
- Handle credit/debit notes carefully: Ensure CDNs are linked to original invoices and reported correctly in the relevant amendment tables.