GST Compliance Checklist 2026: Monthly, Quarterly and Annual Due Dates for Businesses

A GST compliance checklist helps a business answer one question every month: is every GSTIN filed, reconciled and paid on time? GST compliance is not a single return. It is a cycle of outward supply reporting, input tax credit (ITC) checks, tax payment, e-invoicing and annual returns, repeated for every registration you hold. Missing one step usually shows up later as a mismatch notice, interest or lost credit.

This guide sets out the GST compliance list for 2026 by frequency, the rules that changed how returns work, and a GSTIN-level checklist that finance teams and CA firms can run each month.

What GST compliance covers

For a regular taxpayer, GST compliance has five parts:

• Reporting outward supplies in GSTR-1 (or IFF under QRMP).
• Claiming eligible ITC after matching purchases with GSTR-2B and acting on invoices in the Invoice Management System (IMS).
• Paying tax and filing the summary return, GSTR-3B.
• Transaction documents: e-invoices and e-way bills where they apply.
• Annual returns: GSTR-9 and, above the turnover limit, GSTR-9C.

Each GSTIN is a separate taxpayer under GST, so a business registered in five states runs this cycle five times.

Monthly GST compliance list

Due dates fall on the next working day only where the government notifies an extension; check the GST portal before relying on a holiday.

Quarterly GST compliance list

Annual and half-yearly GST compliance

For FY 2025-26, the ITC cut-off is 30 November 2026 and GSTR-9/9C are due on 31 December 2026. Our guides on the GST ITC deadline and on GSTR-9 and GSTR-9C for FY 2025-26 cover both in detail.

Rules that changed how GST compliance works

GSTR-3B is locked for values from GSTR-1

From the July 2025 tax period, the outward-supply liability auto-filled in Table 3 of GSTR-3B from GSTR-1, GSTR-1A or IFF can no longer be edited in GSTR-3B. Corrections have to be made at source, through GSTR-1A, before GSTR-3B is filed. In practice this means GSTR-1 must be right the first time, and sales reconciliation has to happen before the 11th, not after the 20th.

Returns are time-barred after three years

Under amendments made by the Finance Act, 2023 to sections 37, 39, 44 and 52 of the CGST Act, a return cannot be filed after three years from its due date. The GST portal enforces this, so an old unfiled return can no longer be regularised just by filing it late. Clear old defaults while the window is open.

IMS sits between your suppliers and GSTR-2B

Supplier invoices appear in the Invoice Management System, where you can accept, reject or keep them pending. Your actions decide what reaches GSTR-2B and so what ITC you can claim in GSTR-3B. Rejected and pending invoices need a follow-up with the supplier, not just a note in Excel.

E-invoices have a 30-day reporting limit

E-invoicing is mandatory for businesses with aggregate turnover above ₹5 crore in any year since 2017-18. Businesses with turnover of ₹10 crore or more must report each e-invoice to the Invoice Registration Portal within 30 days of the invoice date; the IRP rejects invoices reported later.

Return changes recommended by the 57th GST Council

The GST Council in October 2026 recommended tighter reconciliation between GSTR-1 and GSTR-3B and new statements for RCM and ITC reversals, linked to the April 2027 return period. These are recommendations until notified. See our summary of the 57th GST Council meeting.

ITC rules to check every month

• GSTR-2B match: claim ITC only on invoices that appear in GSTR-2B and match your purchase register.
• Section 17(5): reverse blocked credits such as motor vehicles (with exceptions), food and beverages, and goods for personal use.
• Rule 37: if you have not paid a supplier within 180 days of the invoice date, reverse the ITC and reclaim it when you pay.
• Rule 37A: if a supplier has not filed GSTR-3B for the period by 30 September of the following year, reverse the ITC by 30 November; reclaim it once the supplier files.
• Supplier status: check that suppliers' GSTINs are active before you rely on their invoices. The GST verification API checks registrations in bulk.

RCM: the item most often missed

Under reverse charge, the recipient pays the tax instead of the supplier. Common RCM supplies include legal services from an advocate, goods transport agency services, sponsorship services, and certain supplies by unregistered persons. RCM tax is paid in cash through GSTR-3B; the ITC on it is then available in the same return if the supply is used for business. Issue a self-invoice for RCM purchases from unregistered suppliers, and keep a separate RCM register so the liability is not missed.

GSTIN-level monthly GST compliance checklist

For step 5, our GSTR-2B reconciliation guide explains the invoice-level process. For step 11, NoticeCPC tracks GST notices for all GSTINs with due-date alerts.

How GSTCPC handles GST compliance

GSTCPC is Figment's GST compliance software for enterprises and CA firms. For the checklist above, the relevant features are:

• Return filing for GSTR-1, GSTR-1A, GSTR-3B, GSTR-9 and GSTR-9C, plus GSTR-6, GSTR-7 and ITC-04, with role-based filing controls so returns are reviewed before they are filed.
• GSTR-2A and GSTR-2B reconciliation against the purchase register, with ITC tracking and ITC mismatch reports.
• IMS actions (accept, reject and pending) on supplier invoices.
• A temporary ITC reversal and reclaim ledger for Rule 37 and Rule 37A movements.
• Multiple GSTINs under one organisation, with bulk GSTIN validation.
• E-invoice and e-way bill generation from the same records.

To see how this fits your GSTINs, book a demo of our GST compliance software.

Key takeaways

• GST compliance is a monthly cycle per GSTIN: GSTR-1, IMS and GSTR-2B, ITC checks, GSTR-3B, then the annual return.
• GSTR-3B Table 3 is now locked to GSTR-1, so fix sales data before the 11th.
• Returns cannot be filed more than three years after the due date.
• For FY 2025-26, claim ITC by 30 November 2026 and file GSTR-9/9C by 31 December 2026.
• Keep RCM, Rule 37 and Rule 37A in the monthly checklist, not the year-end one.