What is GSTR-1?
GSTR-1 is a monthly or quarterly return where you declare all outward supplies (sales). It determines what ITC your customers can claim — so accuracy matters for everyone you supply, not just you.
Who Files It
- Every regular GST taxpayer (not composition dealers, ISDs, NRTPs, TDS/TCS deductors)
- NIL returns mandatory even with zero sales
- QRMP filers can upload invoices monthly via IFF but submit GSTR-1 quarterly
Due Dates
- Monthly filers — 11th of the following month
- QRMP filers — 13th of the month after the quarter
- IFF (optional monthly upload for QRMP) — 13th of the following month
Information You Need
- All sales invoices — invoice number, date, value, tax
- Customer GSTIN (B2B sales)
- State code of customer (to determine IGST vs CGST+SGST)
- HSN/SAC code for each product/service
- Credit notes and debit notes issued
- Advances received and adjusted
- Export invoices with shipping bill details
The Tables of GSTR-1
| Table | Covers |
|---|---|
| 4A, 4B, 4C | B2B invoices — to registered persons |
| 5A, 5B | B2C large — inter-state, over ₹2.5 lakh |
| 6A | Exports of goods and services |
| 7 | B2C summary — small intra-state and inter-state aggregated |
| 8 | Nil-rated, exempt, non-GST supplies |
| 9A, 9B, 9C | Credit/debit notes, amendments |
| 11A, 11B | Advances received and adjusted |
| 12 | HSN-wise summary of outward supplies |
| 13 | Documents issued — invoice/CN/DN ranges |
Step-by-Step Filing
- Log in at gst.gov.in → Services → Returns → Returns Dashboard. Select year and period.
- Click "Prepare Online" (low volume) or download the Offline Tool and upload JSON (high volume).
- Fill B2B section — for each invoice, enter customer GSTIN, invoice details, place of supply, RCM flag, tax rate, taxable value, IGST or CGST+SGST.
- Complete HSN summary (Table 12) — for each unique HSN, enter quantity, taxable value, tax.
- Save and Preview — verify every number against your books.
- Submit and File — DSC (companies) or EVC (proprietorships). On success you get the ARN.
HSN Reporting Rules
- Turnover ≤ ₹5 crore — 4-digit HSN for B2B; optional for B2C
- Turnover > ₹5 crore — 6-digit HSN mandatory for all
- Exports/imports — 8-digit HSN always
Common Mistakes
- Wrong place of supply → IGST/CGST/SGST mismatch
- Typo in customer GSTIN → invoice rejected, customer can't claim ITC
- Missing invoices → caught later at GSTR-9
- Wrong HSN code → 6-digit codes mandatory above ₹5 crore
- Filing GSTR-3B before GSTR-1 → leads to mismatch and notice
Once filed, GSTR-1 cannot be revised. Errors must be corrected through amendments in the next month's return (Tables 9A/9B/9C/10).
In iAccounting
iAccounting generates GSTR-1 JSON in one click — already in the exact format the portal expects. 200-invoice filing that takes 3 hours manually becomes 15 minutes.
See it in action →Continue Learning
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