GSTR-1, GSTR-3B & GSTR-9 Filing Calendar for FY 2026-27

Introduction

Timely GST return filing is one of the most critical compliance requirements for every registered taxpayer. Failure to file returns within the prescribed due dates may result in late fees, interest liabilities, blockage of Input Tax Credit (ITC), notices from the GST department, and cancellation of GST registration in extreme cases.

For Financial Year (FY) 2026-27, taxpayers should maintain a clear GST compliance calendar to ensure timely filing of GSTR-1, GSTR-3B, and GSTR-9. This article provides a comprehensive filing calendar along with important compliance considerations.

Understanding GST Returns

GSTR-1

GSTR-1 is a statement of outward supplies containing details of:

• B2B sales
• B2C sales
• Exports
• Credit Notes
• Debit Notes
• Amendments to previous invoices

The details reported in GSTR-1 flow into the recipient's GSTR-2B and are used for claiming Input Tax Credit.

GSTR-3B

GSTR-3B is a summary return through which taxpayers:

• Report outward supplies
• Claim Input Tax Credit
• Discharge GST liability
• Pay tax dues

It is the primary monthly compliance return under GST.

GSTR-9

GSTR-9 is the Annual Return that consolidates information reported in:

• GSTR-1
• GSTR-3B
• Financial Statements

It serves as an annual reconciliation of GST transactions.

GSTR-1 Filing Due Dates for FY 2026-27

Monthly Filers

Quarterly Filers (QRMP Scheme)

GSTR-3B Filing Due Dates for FY 2026-27

Monthly Taxpayers

QRMP Taxpayers

The due date for GSTR-3B under QRMP Scheme generally falls on:

(The exact due date depends upon the State/UT classification notified by the GST Department.)

GSTR-9 Due Date for FY 2026-27

Subject to any extension notified by the Government.

Important GST Compliance Timeline

Reconciliation Before GSTR-3B Filing

Before filing GSTR-3B, taxpayers should reconcile:

• Sales register vs GSTR-1
• Purchase register vs GSTR-2B
• E-way bills
• E-invoices
• Electronic Credit Ledger
• Electronic Cash Ledger

September Cut-Off Compliance

The GST law imposes important timelines relating to:

• ITC claims
• Debit Note claims
• Credit Note adjustments
• Amendments to invoices

Businesses should ensure that all reconciliations are completed well before the statutory cut-off dates applicable under GST law.

Late Fees for Delayed Filing

GSTR-1

Late filing attracts:

• CGST Late Fee
• SGST Late Fee

subject to prescribed caps.

GSTR-3B

Late filing results in:

• Late Fees
• Interest on tax liability
• Blocking of E-way Bill generation in certain cases

GSTR-9

Delayed filing of annual return attracts late fees as prescribed under GST provisions.

Consequences of Non-Filing

Failure to file GST returns may lead to:

• GST Notices
• Suspension of GST Registration
• Cancellation of GST Registration
• ITC mismatch issues
• Vendor disputes
• Additional scrutiny by tax authorities

Best Practices for GST Compliance in FY 2026-27

1. Maintain Monthly Reconciliation

Match books with GST portal records every month.

2. Reconcile GSTR-2B Regularly

Claim ITC only after proper verification.

3. Verify E-Invoice Data

Ensure consistency between invoices and GST returns.

4. Track Vendor Compliance

Monitor whether vendors are filing GST returns on time.

5. Maintain Annual GST Working Papers

This significantly simplifies GSTR-9 preparation.

GST Compliance Checklist for Businesses

✔ GSTR-1 filed on time
✔ GSTR-3B filed on time
✔ Tax liability paid before due date
✔ ITC reconciled with GSTR-2B
✔ E-way bills reconciled
✔ E-invoices matched with books
✔ Vendor compliance reviewed
✔ Annual reconciliation completed

Conclusion

GSTR-1, GSTR-3B, and GSTR-9 are the backbone of GST compliance. A well-maintained GST filing calendar helps businesses avoid penalties, improve ITC management, and maintain smooth operations. For FY 2026-27, taxpayers should proactively track return due dates, perform monthly reconciliations, and maintain proper documentation to ensure complete GST compliance.