How to File GSTR-1 in 2026 — Complete Guide with Examples
By Parul Singh, GST Practitioner · GST Returns
Table of Contents
Every month, my team files 200+ GSTR-1 returns for businesses across Delhi. The most common error I see is wrong GSTINs — even one wrong digit means your buyer cannot claim ITC.
GSTR-1 is the return for reporting all outward supplies (sales) made during a tax period. It must be filed by every registered taxpayer, and the data in GSTR-1 auto-populates the recipient's GSTR-2A for ITC matching.
Who Must File GSTR-1
All regular registered taxpayers must file GSTR-1. Taxpayers under the composition scheme file CMP-08 instead. The frequency depends on your turnover — monthly for turnover above ₹1.5 crore, quarterly otherwise.
Due Dates for 2026
| Period | Monthly Filing | QRMP Scheme |
|---|---|---|
| January 2026 | 11 February | 13 April (Q4) |
| February 2026 | 11 March | 13 April (Q4) |
| March 2026 | 11 April | 13 April (Q4) |
Late fee: ₹50/day (₹20 for nil returns), maximum ₹5,000.
Key Tables in GSTR-1
- Table 1: B2B Invoices — sales to registered dealers
- Table 2: B2C Large — invoices above ₹2.5 lakh (inter-state)
- Table 3: B2C Small — consolidated supplies below threshold
- Table 4: Credit/Debit Notes
- Table 5: Exports (with/without payment)
- Table 6: Tax liability on advance received
- Table 7: Amendments to previous returns
Step-by-Step Filing Process
- Login to gst.gov.in → Services → Returns → Returns Dashboard
- Select financial year and return filing period
- Click "Prepare Offline" or "Prepare Online"
- Fill in all applicable tables or upload JSON file
- Verify all entries — compare with your sales register
- Click "Generate GSTR-1 Summary"
- Review summary and click "Submit"
- File using DSC or EVC (Aadhaar OTP)
Tip: Use the offline utility tool for bulk uploads. Always reconcile your GSTR-1 with your books of accounts before filing to avoid mismatches.