How to File GSTR-1 in 2026

Who must file GSTR-1?

GSTR-1 must be filed by every registered taxpayer who makes outward taxable supplies. This includes regular taxpayers under the monthly scheme and those who have opted for the QRMP (Quarterly Return Monthly Payment) scheme.

• All regular GST taxpayers with aggregate turnover above the exemption threshold
• Casual taxable persons for the period of their registration
• SEZ units and SEZ developers for their outward supplies
• E-commerce operators required to collect tax at source under Section 52

Exempt from GSTR-1: Composition dealers (file GSTR-4 annually and CMP-08 quarterly), Input Service Distributors, non-resident taxable persons, persons paying TDS under Section 51, and persons supplying OIDAR services from outside India.

What are the GSTR-1 filing due dates in 2026?

The due date depends on whether you file monthly or have opted for the QRMP scheme. QRMP is available to taxpayers with aggregate annual turnover up to ₹5 crore.

QRMP filers also have an optional Invoice Furnishing Facility (IFF) for the first two months of each quarter, which allows B2B invoice details to flow to buyers' GSTR-2B even before the quarterly GSTR-1 is filed. IFF is due by the 13th of the following month.

For the April–June 2026 quarter, the QRMP GSTR-1 due date is 13 July 2026. For monthly filers, the June 2026 return is due 11 July 2026.

What are the key tables in GSTR-1?

GSTR-1 has thirteen tables (some with sub-tables). You will typically only fill a subset depending on the nature of your sales.

• Table 4 (B2B invoices): Invoice-level details for all supplies to registered businesses (GSTIN holders). Each invoice requires: GSTIN of recipient, invoice number, date, value, place of supply, tax rate, and CGST/SGST/IGST amounts.
• Table 5 (B2C large): Invoice-level details for B2C (unregistered) supplies where the invoice value exceeds ₹2.5 lakh and the supply is inter-state.
• Table 6 (Exports — 6A): Export invoices with or without payment of IGST. Shipping bill number, date, and port code are required where available.
• Table 7 (B2C small — rate-wise summary): Consolidated state-wise summary of all B2C supplies not reported in Table 5. No invoice-level detail needed.
• Table 9 (Amendments to B2B): Corrections to B2B invoices reported in earlier periods. Use this instead of deleting and re-uploading.
• Table 9B (Credit/debit notes for B2B): Credit notes and debit notes issued to registered customers.
• Table 10 (Credit/debit notes for B2C): Credit notes and debit notes issued for unregistered customers.
• Table 11 (Advances received): Advances received against future supplies on which GST is applicable. Rarely used since the 2022 exemption for small taxpayers.
• Table 12 (HSN summary): Summary of outward supplies, HSN/SAC code-wise, with quantity and tax values. Mandatory for all taxpayers with turnover above ₹5 crore from FY 2021–22 onwards.
• Table 13 (Documents issued): Count of tax invoices, credit notes, debit notes, and revised invoices issued during the period.

How do you report B2B invoices in GSTR-1?

B2B invoices go in Table 4. Each invoice must be reported individually — there is no aggregation for B2B in GSTR-1, because each invoice directly affects a specific buyer's GSTR-2B and ITC claim.

• Go to Table 4 on the GSTN portal or in your GST software
• Enter the recipient's GSTIN — the portal validates it automatically
• Enter invoice number, invoice date, and total invoice value
• Select the place of supply (state code) — this determines whether CGST+SGST or IGST applies
• Enter the taxable value and the applicable tax rates/amounts for each rate slab on the invoice
• Mark whether the supply is subject to reverse charge

If you use accounting software like Ledgester, the system auto-populates Table 4 from your recorded sales invoices and pushes the data directly to the GSTN API, eliminating manual entry.

Tip: For e-invoice-enabled taxpayers, the IRP automatically pre-populates Table 4 with data from uploaded IRNs. Review and correct any missing invoices before submitting.

How do you report B2C sales in GSTR-1?

B2C reporting in GSTR-1 depends on the invoice value and whether the supply is intra-state or inter-state.

• Inter-state invoices above ₹2.5 lakh: report invoice-by-invoice in Table 5 (B2C large). Each invoice needs value, place of supply, and tax details.
• All other B2C supplies (intra-state any value, inter-state below ₹2.5 lakh): aggregate state-wise and rate-wise in Table 7 (B2C small). No individual invoice detail needed.
• Advances received: if applicable, report in Table 11 with the state of the recipient and the tax rate.

For most small and medium businesses, the majority of B2C sales go into Table 7 as a consolidated entry, making that table straightforward to complete. Ensure your accounting software splits intra-state and inter-state B2C correctly.

How do you amend a GSTR-1 already filed?

GSTR-1 does not have a revision facility. Corrections to data reported in a previous period are made in the current period's GSTR-1 using the amendment tables.

• Amend a B2B invoice (Table 9): select the original invoice from a previous period, enter the revised values. The system shows the original and the difference.
• Amend a B2C large invoice (Table 10): same process — locate and revise the original record.
• Amend exports (Table 9A): for corrections to export invoice data filed in Table 6A of a prior period.
• Credit and debit notes (Tables 9B and 10): issue a credit note (for reductions) or debit note (for additions) when the original invoice value changes post-supply.

Amendment data flows to buyers' GSTR-2B in the period when the amendment is filed, not retroactively. Inform your buyers when you make significant amendments so they can reconcile their ITC accordingly.

What are the common GSTR-1 mistakes that affect your buyer's ITC?

Errors in GSTR-1 have a direct impact on your buyers' ability to claim input tax credit. These are the most common mistakes to watch for.

• Wrong GSTIN of the buyer: the invoice will not appear in the correct party's GSTR-2B, denying them ITC. Always verify GSTINs before uploading.
• Wrong place of supply: applying IGST when CGST+SGST was due (or vice versa) creates a mismatch in the buyer's ITC and triggers notices.
• Reporting B2B invoices as B2C: a registered buyer's invoice entered in Table 7 does not flow to their GSTR-2B. Their ITC is blocked until you amend it to Table 4.
• Wrong invoice number or date: minor typos in invoice numbers prevent buyers from reconciling their purchase register with GSTR-2B.
• Filing GSTR-1 after GSTR-3B: your buyers' GSTR-2B for a period is finalized based on your GSTR-1 for that period. If you file GSTR-3B before GSTR-1, your invoices miss that period's GSTR-2B cut-off.
• Not filing at all: your buyers' GSTR-2B will not include any of your invoices until you file. Late filing directly blocks their ITC for the period.