GSTR-1 Filing Guide — How to File Outward Supplies Return in India

GSTR-1 is the most important GST return for most businesses — it declares all your outward supplies (sales and exports) for the period. Getting GSTR-1 right matters because it directly affects your customers' ability to claim Input Tax Credit (ITC). An error in your GSTR-1 means your customer's ITC gets blocked. Here is a complete guide to filing GSTR-1 accurately.

What is GSTR-1?

GSTR-1 is the monthly or quarterly return that reports all outward supplies (sales of goods and services) made by a GST-registered taxpayer during the period. It includes B2B invoices, B2C invoices, exports, debit notes, credit notes and advances received.

The data you file in GSTR-1 is auto-populated into your customers' GSTR-2B (ITC ledger). This is why accuracy is critical — an error that affects ITC auto-population can cause disputes with your buyers.

Who Must File GSTR-1?

• All regular GST-registered taxpayers (monthly or quarterly)
• SEZ developers and SEZ units
• Casual taxable persons
• Non-resident taxable persons

Composition scheme dealers, Input Service Distributors (ISDs) and non-resident taxable persons file different returns and are not required to file GSTR-1.

Key Tables in GSTR-1

Table 4 — B2B Invoices: Invoice-level details for all supplies to GST-registered recipients (other businesses). You must enter the GSTIN of the recipient, invoice number, date, value and GST amount for each invoice.

Table 5 — B2C (Large) Invoices: Individual invoices above ₹2.5 lakh to unregistered recipients (consumers). State-wise summary is reported.

Table 6 — Exports: All export invoices with shipping bill details (for with-payment exports) or without payment (for LUT exports).

Table 7 — B2C (Small) Summary: Consolidated state-wise summary of all invoices below ₹2.5 lakh to unregistered recipients.

Table 8 — Nil, Exempt and Non-GST Supplies: Summary of supplies that are nil-rated, exempt or not subject to GST.

Table 9 — Amendments: Amendments to invoices of previous tax periods.

Table 11 — Advance Receipts: GST on advances received for which supplies have not yet been made (applicable for services).

Table 12 — HSN Summary: HSN-wise summary of outward supplies. Mandatory for taxpayers with turnover above ₹5 crore (6-digit HSN) and above ₹1.5 crore (4-digit HSN).

Step-by-Step GSTR-1 Filing Process

Step 1: Log in to the GST portal (gst.gov.in) with your credentials.

Step 2: Navigate to Returns Dashboard → Select the financial year and tax period → Click GSTR-1 → Prepare Online or upload JSON file.

Step 3: Enter invoice details in the relevant tables. For businesses with large invoice volumes, use the offline utility (Excel template) to prepare data and upload as JSON.

Step 4: Generate and verify the preview. Check the computed tax liability.

Step 5: Submit GSTR-1 using DSC (for companies) or EVC (for individuals/proprietorships). Once submitted, GSTR-1 cannot be revised but can be amended in the next period.

Common Mistakes in GSTR-1

• Wrong GSTIN of the recipient (causes ITC mismatch for the buyer)
• Missing export shipping bill details
• Incorrect HSN codes
• Not filing NIL GSTR-1 (even if there are no supplies)
• Missing debit note / credit note entries

Conclusion

GSTR-1 accuracy directly impacts your business relationships and your customers' cash flow through ITC. SPOTON's GST filing team handles GSTR-1 for hundreds of Kerala businesses every month, ensuring data accuracy and zero ITC disputes. Get in touch for professional GST filing services.