How to File GSTR-1 Return Online: Complete Step-by-Step Guide (2025)

What is GSTR-1?

GSTR-1 is a monthly or quarterly return that every GST-registered taxpayer must file to report their outward supplies (sales) made during the period. It is the primary document through which the GST system tracks your sales, and it directly feeds into your buyer's GSTR-2A and GSTR-2B — enabling them to claim Input Tax Credit (ITC).

Filing an accurate GSTR-1 is not just a compliance requirement — it directly impacts your buyers' ability to claim ITC. Any error or delay on your part can cause problems for your customers.

Who Must File GSTR-1?

• All regular GST-registered taxpayers (monthly or quarterly under QRMP)
• e-Commerce operators (for supplies made through their platform)
• Exempted from GSTR-1: Composition dealers (they file CMP-08 + GSTR-4), TDS deductors (GSTR-7), Input Service Distributors (GSTR-6)

Due Dates

Filing Frequency	Due Date
Monthly (turnover > ₹5 crore)	11th of the following month
Quarterly (QRMP scheme)	13th of the month following the quarter
IFF (Invoice Furnishing Facility)	13th of months 1 & 2 of the quarter

Understanding the GSTR-1 Tiles

GSTR-1 is divided into 13 tiles (sections). Here's what each tile covers:

Tile 4 — B2B (Business to Business) Invoices

Report all invoices raised to registered buyers (those with a GSTIN). For each invoice, enter the buyer's GSTIN, invoice number, date, taxable value, GST rate, and applicable IGST/CGST/SGST/Cess. This is the most critical tile — data here directly feeds the buyer's GSTR-2B for ITC claim.

Key points: If you have an active IRN (e-Invoice), the source appears as "e-Invoice" and the IRN/IRN date are auto-populated. Editing such rows is blocked unless the IRN is cancelled.

Tile 5 — B2CS (Business to Consumer Small)

Report intra-state supplies to unregistered buyers where invoice value is ₹2.5 lakh or less. Data is entered state-wise and rate-wise — individual invoice details are not required.

Tile 6 — B2CL (Business to Consumer Large)

Report inter-state supplies to unregistered buyers where invoice value exceeds ₹2.5 lakh. Individual invoice details are required here.

Tile 7 — Exports (EXPWP / EXPWOP)

Report exports made with payment of IGST (EXPWP) or without payment under LUT/Bond (EXPWOP). Shipping bill number and date are required.

Tile 8 — Credit/Debit Notes (CDN Reg)

Report credit notes and debit notes issued to registered buyers. Enter the original invoice reference along with revised values.

Tile 9 — CDN Unreg

Credit/debit notes issued to unregistered buyers for B2CL supplies (inter-state, value > ₹2.5 lakh).

Tile 12 — HSN Summary

Report a summary of outward supplies categorised by HSN (Harmonised System of Nomenclature) code. Mandatory for businesses with aggregate turnover above ₹5 crore (6-digit HSN) and ₹1.5 crore to ₹5 crore (4-digit HSN).

Tile 13 — Documents Issued

Report the serial number range of all documents issued during the period — tax invoices, revised invoices, debit notes, credit notes, delivery challans, and e-Way Bills.

Step-by-Step Filing Process

1. Log in to the GST portal and navigate to Returns → File Returns → GSTR-1.
2. Select the period (month/quarter) for which you are filing.
3. Fill each tile — start with Tile 4 (B2B) as it is the most important. You can add invoices manually or import via JSON/Excel.
4. Auto-populate HSN summary using the "Import from e-Invoice" button if you have IRN-linked invoices.
5. Review the summary — check totals before proceeding.
6. Submit the return — click Submit to freeze data (cannot edit after this).
7. File with DSC or EVC — digitally sign using DSC or verify via OTP sent to your registered mobile/email.
8. Note your ARN — the Application Reference Number confirms successful filing.

Late Fee

If you miss the due date, late fees apply from the day after the due date:

• Nil return: ₹10/day (₹5 CGST + ₹5 SGST) up to a maximum of ₹500
• Other returns: ₹25/day (₹12.50 CGST + ₹12.50 SGST) up to a maximum of ₹5,000 per return

Common Mistakes to Avoid

• Entering wrong GSTIN for buyers — causes ITC mismatch in their GSTR-2B
• Not reporting zero-rated supplies (exports/SEZ) — affects refund eligibility
• Skipping the HSN tile — mandatory above threshold; attracts notice
• Forgetting to file IFF for months 1 & 2 under QRMP — your buyers won't see your invoices in their GSTR-2B

Practice GSTR-1 Filing on IndIaTaxSim

The best way to master GSTR-1 is hands-on practice. IndIaTaxSim provides a pixel-perfect simulation of the real GST portal where you can:

• Add B2B, B2CS, CDN, and HSN entries exactly like the real portal
• Generate e-Invoices (IRN) and see them auto-populate GSTR-1 Tile 4
• Generate GSTR-1 JSON in GSTN format (v3.3.4)
• Experience the complete filing workflow — Submit → File with EVC
• Practice GSTR-1A amendments and IFF for QRMP taxpayers

All 80 course modules walk you through the real workflow step by step. Sign up free and get 1 credit to start practising today.