A Complete Guide to GSTR-1 Filing: Format, Tables, Due Dates & Latest Updates

All regular registered taxpayers making outward supplies are generally required to filGSTR-1. Certain categories file other returns instead, such as composition taxpayers, non-resident taxable persons, ISDs, TDS deductors, TCS e-commerce operators, and OIDAR service providers.

Even if there are zero outward supplies in a period, a NIL GSTR-1 is still required for an eligible filer.

The GST portal states that GSTR-1 is generally due on the 11th of the succeeding month for monthly filers and on the 13th of the month following the quarter for quarterly filers. QRMP is available to eligible taxpayers with aggregate annual turnover up to ₹5 crore, subject to the scheme conditions.

FY 2026-27 quarterly due dates

A taxpayer is not allowed to furnish GSTR-1 in certain blocking situations, including specified non-filing defaults and other portal-level restrictions under Rule 59. Separately, section 37 also carries a 3-year outer limit for furnishing the details of outward supplies.

Several practical changes matter for FY 2025-26 filing.

The GST portal’s current GSTR-1 flow includes outward supply reporting tables, amendment tables, HSN summary, document summary, and e-commerce related tables. The descriptions below reflect the current broad table treatment used on the portal.

Tables 1 to 3: Basic registration details

No manual entry is usually needed in these opening tables.

Table 4: Taxable outward supplies made to registered persons

This table captures B2B supplies. It includes regular taxable supplies to registered persons, reverse charge related categories where applicable in the reporting structure, and supplies made through e-commerce operators where required in the table design. In practice, invoice-level accuracy matters here because GSTIN, invoice number, tax rate, place of supply , and tax amounts affect downstream matching and recipient visibility.

Table 5: B2CL

From the August 2024 tax period onward, Table 5 covers taxable outward inter-state supplies made to unregistered persons where the invoice value is more than ₹1 lakh, including supplies made through e-commerce operator, rate wise. This is one of the most important corrections from your draft, because the old ₹2.5 lakh threshold is no longer the current position for these return periods.

Table 6: Zero-rated supplies and deemed exports

This table is used for exports and supplies to SEZ, with or without payment of tax, and related outward supply categories covered by the portal structure. Where shipping bill details are relevant, accuracy is important for proper linkage and refund-related workflows.

Table 7: B2CS

Table 7 captures B2C other supplies, which broadly include intra-state supplies to unregistered persons and inter-state supplies to unregistered persons that do not fall into the revised B2CL category. These are reported in summary form rather than invoice by invoice in the usual workflow.

Table 8: Nil-rated, exempt, and non-GST outward supplies

This table captures consolidated details of nil-rated, exempt, and non-GST outward supplies. Under GST, exempt supply includes nil-rated supplies, wholly exempt supplies, and non-taxable supplies.

Tables 9 to 11: Amendments and advance-related reporting

The portal includes amendment tables for earlier B2B, B2CL, export, credit note, debit note, B2C, and advance-related entries. Use these tables to correct prior period disclosures instead of re-reporting the original transaction in the wrong table for the current period.

Table 12: HSN-wise summary of outward supplies

From the May 2025 tax period onward, Table 12 is bifurcated into two tabs, B2B Supplies and B2C Supplies. The portal validates HSN reporting based on turnover. For taxpayers with turnover up to ₹5 crore, less than 4 digits triggers an error. For taxpayers above ₹5 crore, the required reporting threshold is stricter. The portal also states that, in the May 2025 onward flow, HSN should be selected from the drop-down and invalid HSN is not allowed to proceed.

Table 13: Documents Issued

Table 13 captures document summary details for the tax period. From the current portal logic for the revised flow, if the taxpayer has entered data in specified operative tables and leaves Table 13 blank, the system blocks summary generation. In practical terms, treat Table 13 as mandatory where active outward supply reporting exists in those linked tables.

Table 14: Supplies made through ECO

The GST portal’s current table list describes Table 14 as Supplies made through ECO. It should be explained as a dedicated reporting table for supplies made through e-commerce operators in the current return framework, not as a generic reverse charge summary.

Table 15: Supplies under section 9(5)

Table 15 captures supplies covered under Section 9(5) of the CGST Act, where GST liability applies to notified supplies made through e-commerce operators as per the portal’s classification.

Taxpayers with aggregate annual turnover up to ₹5 crore in the current and preceding financial year, subject to the prescribed conditions, can opt for QRMP. Under QRMP, GSTR-1 is filed quarterly, while tax is paid monthly through the QRMP mechanism.

The Invoice Furnishing Facility, or IFF, is available to QRMP filers for Month 1 and Month 2 of the quarter. It allows reporting of eligible B2B invoices, credit notes, and debit notes up to the prescribed monthly value cap so that recipients can see those invoices earlier instead of waiting for the quarterly GSTR-1.

IFF is especially useful where your customers are registered businesses that want timely invoice reflection for their monthly ITC workflow.

E-invoicing currently applies to taxpayers crossing the notified turnover threshold of ₹5 crore and above, subject to the notified scope and exclusions. It covers specified documents such as B2B invoices and certain related documents.

E-invoicing does not replace GSTR-1. It only changes how some invoice data flows into the system. Even where invoice data is generated through the IRP, the taxpayer still needs to review and file the complete GSTR-1 return. Other sections such as B2C supplies, HSN summary, document summary, and non-auto-populated disclosures still need attention.

For businesses looking to manage this workflow end-to-end, e-invoicing software like BUSY generates IRN-compliant invoices and syncs the data directly into your GSTR-1 preparation flow.

A practical point here is that e-invoicing reduces duplicate manual work, but it does not remove the need for return review, table completeness checks, and final filing discipline.

How to File GSTR-1 on the GST Portal

1. Log in to the GST portal.
2. Go to Services, then Returns, then Returns Dashboard.
3. Select the financial year and return period.
4. Open GSTR-1 and choose the appropriate preparation mode.
5. Fill the relevant tables or review the system-populated data where applicable.
6. Generate the return summary.
7. Verify values against books, sales register, and supporting records.
8. Submit and file using DSC or EVC, as applicable.

Businesses using accounting software integrated with the GST portal can auto-populate invoice data into the relevant GSTR-1 tables, reducing manual entry errors and speeding up return review before filing.

Pre-filing checklist

• All applicable outward supplies reported
• Correct B2CL threshold applied at more than ₹1 lakh for relevant return periods
• Table 12 completed under the correct B2B and B2C tabs where applicable
• Table 13 completed where the system requires it
• HSN selected correctly with turnover-based digit compliance
• Prior blocking issues under Rule 59 checked
• Bank account details furnished as required under Rule 10A

How to File a NIL GSTR-1

If there are no outward supplies during the tax period, a NIL GSTR-1 still needs to be filed by the eligible taxpayer. This can be done through the portal, and in permitted cases through the NIL filing facility for relevant filers.

The practical rule is simple: no sales does not mean no return. Skipping the NIL filing can create avoidable compliance backlog and can also trigger filing restrictions for future periods.

Section 47 of the CGST Act provides the statutory late fee framework for delay in furnishing outward supply details. In practice, the reduced late fee regime for GSTR-1 and GSTR-3B has been widely applied based on the post-2021 rationalised structure commonly reflected in GST compliance guidance. The daily late fee is typically ₹50 per day for regular returns and ₹20 per day for NIL returns , with slab-based caps.

Interest does not apply merely because GSTR-1 is filed late. Interest is linked to delayed tax payment, which is generally relevant to GSTR-3B and tax discharge, not to outward supply reporting by itself.

Also, be careful with the e-Way Bill . The common operational trigger for e-Way Bill blocking is not simply late GSTR-1. The official GST guidance ties blocking primarily to non-filing of GSTR-3B or CMP-08 for the prescribed consecutive periods.

GSTR-1A is available as an optional amendment facility after GSTR-1 is filed and before GSTR-3B is filed for the same tax period. The GST portal FAQ states that taxpayers can use GSTR-1A to add records missed in GSTR-1 and to amend records already reported in GSTR-1 for the same period.

This means GSTR-1A is useful where you discover a missed invoice, a wrong invoice value, a tax error, or another correctable outward supply reporting issue before filing GSTR-3B for that period. It is better to describe GSTR-1A as a supplier-side correction window, not merely as a place where buyer-flagged mismatches appear. The current ecosystem also interacts with IMS, where recipients can accept, reject, or keep records pending.

After Filing: Reconcile GSTR-1 with GSTR-2B and IMS

After filing GSTR-1, the compliance job is not over. Supplier data flows into the recipient-side ITC environment, including GSTR-2B and IMS-related workflows. If invoice details are wrong, missing, delayed, or assigned to the wrong GSTIN, the recipient may face ITC reflection issues or reconciliation disputes.

Supplier data flows into the recipient-side ITC environment. Proper GST reconciliation . between your filed GSTR-1 and the recipient's GSTR-2B view is essential to avoid ITC disputes.

Practical reconciliation steps

1. Match filed GSTR-1 data with your sales register.
2. Verify recipient GSTIN, invoice number, invoice date, taxable value, and tax amount.
3. Review credit notes and debit notes separately.
4. Confirm whether key B2B invoices have flowed correctly into the recipient-side view.
5. Use GSTR-1A, where still available for the period, or amendment tables in the next eligible return cycle for corrections.

A GSTR reconciliation software can match your GSTR-1 data against GSTR-2B automatically, flagging mismatches before they affect your buyers' ITC claims.

Conclusion

GSTR-1 is the core outward supply return under GST. For FY 2025-26 the most important GST compliance checkpoints are: use the correct due date based on your filing category, apply the revised B2CL threshold of more than ₹1 lakh for the relevant tax periods, complete Table 12 using the B2B and B2C split from May 2025 onward, fill Table 13 where the system requires it, and use GSTR-1A for same-period corrections before GSTR-3B where needed.

Businesses under QRMP should use IFF where early B2B invoice visibility matters to customers. Businesses under e-invoicing should not assume that IRP reporting ends the compliance process. Accurate return review, correct table selection, and timely filing still matter.