Documents Required for GSTR-1 & GSTR-3B Monthly Filing in India
Accurate monthly GST filing is the backbone of a compliant business in India. By June 2026, the regulatory landscape continues to demand precision from businesses across sectors and states. This guide outlines exactly what documents you must gather before logging into the GST portal for GSTR-1 (outward supplies) and GSTR-3B (summary return). Missing even a single invoice or mismatching HSN codes can lead to penalties, interest charges, and blocked Input Tax Credit.
Before you start
- Ensure your GSTIN is active and linked with valid PAN/Aadhaar details on the portal.
Step-by-step
Gather Outward Supply Invoices
Collect all tax-invoice copies for B2B, B2C (over ₹50k), and exports from your fiscal year. Ensure each invoice has a valid UIN or GSTIN of the recipient to avoid discrepancies in GSTR-1.
Compile E-Way Bill Details
Extract all generated E-way bills for goods movement during the month, including Challan IDs and vehicle numbers. These must match your outward supply entries in Form GST ITC-02 or GSTR-1.
Review Advance Tax Payments
Verify payments made via challans (Form CHA) to ensure they are reflected correctly before filing GSTR-3B. This step is critical for calculating the correct tax liability and avoiding interest under Section 50.
Prepare ITC Reconciliation Sheet
Create a detailed sheet matching your Input Tax Credit (ITC) claimed against GSTR-2B data. Identify any blocked credits or mismatches that need rectification before finalizing the return.
Verify Export Documentation
For exporters, gather shipping bills and Bill of Lading details to ensure exports are reported correctly in GSTR-1 under Schedule II. This ensures you do not face disallowance on zero-rated supplies.
Common mistakes to avoid
- Failing to upload e-invoices for B2C transactions exceeding ₹50,000.
- Not reconciling ITC claimed in GSTR-3B with the actual credit available under Form GST ITC-01.
Frequently asked questions
What is the deadline for filing monthly returns?
The due date typically falls on the 20th of the following month. For example, April's return must be filed by May 20.
Can I file GSTR-1 and GSTR-3B separately?
Yes, you can file them independently, but ensure data consistency to avoid mismatches that trigger notices from the GST department.
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