Managing GST compliance for multiple clients means keeping track of dozens of due dates every month. Missing a single deadline can attract late fees and interest — not to mention the loss of client trust. This comprehensive GST compliance calendar for 2026 covers all major return due dates. Bookmark it, share it with your team and refer to it at the start of every month.
Monthly GST Due Dates (All Months of 2026)
For monthly filers — businesses with turnover above Rs 5 crore — the key due dates repeat every month. Here are the critical dates to track for each month of 2026:
- January 2026: GSTR-1 by January 11 | GSTR-3B by January 20
- February 2026: GSTR-1 by February 11 | GSTR-3B by February 20
- March 2026: GSTR-1 by March 11 | GSTR-3B by March 20
- April 2026: GSTR-1 by April 11 | GSTR-3B by April 20
- May 2026: GSTR-1 by May 11 | GSTR-3B by May 20
- June 2026: GSTR-1 by June 11 | GSTR-3B by June 20
- July 2026: GSTR-1 by July 11 | GSTR-3B by July 20
- August 2026: GSTR-1 by August 11 | GSTR-3B by August 20
- September 2026: GSTR-1 by September 11 | GSTR-3B by September 20
- October 2026: GSTR-1 by October 11 | GSTR-3B by October 20
- November 2026: GSTR-1 by November 11 | GSTR-3B by November 20
- December 2026: GSTR-1 by December 11 | GSTR-3B by December 20
Note: GSTR-1 due date falls on the 11th for monthly filers. GSTR-3B due date is the 20th for monthly filers with turnover above Rs 5 crore. For QRMP scheme filers, the GSTR-3B due date is the 22nd or 24th depending on the state category. These dates may be extended by government notification — always verify with the official GST portal or government circulars.
Quarterly GST Due Dates 2026
For businesses under the QRMP (Quarterly Return Monthly Payment) scheme — turnover up to Rs 5 crore — GSTR-1 is filed quarterly and GSTR-3B is also quarterly. Tax is paid monthly via PMT-06 challan:
- Q1 (April to June 2026): GSTR-1 by July 31 | GSTR-3B by July 22 (Category I states) or July 24 (Category II states) | Monthly PMT-06 payment by 25th of April and May
- Q2 (July to September 2026): GSTR-1 by October 31 | GSTR-3B by October 22 or October 24 | Monthly PMT-06 payment by 25th of July and August
- Q3 (October to December 2026): GSTR-1 by January 31 | GSTR-3B by January 22 or January 24 | Monthly PMT-06 payment by 25th of October and November
- Q4 (January to March 2026): GSTR-1 by April 30 | GSTR-3B by April 22 or April 24 | Monthly PMT-06 payment by 25th of January and February
- IFF (Invoice Furnishing Facility): Available for months 1 and 2 of each quarter — deadline is the 13th of the month following each of those months
Annual GST Return Due Dates 2026
- GSTR-9 (Annual Return for FY 2025-26): December 31, 2026 — mandatory for taxpayers with aggregate turnover above Rs 2 crore
- GSTR-9C (Reconciliation Statement for FY 2025-26): December 31, 2026 — applicable for taxpayers with turnover above Rs 5 crore, self-certified by the taxpayer
- GSTR-9A (Annual Return for Composition Taxpayers): December 31, 2026 — for businesses under the composition scheme
Other Important GST Compliance Dates
- GSTR-7 (TDS under GST by deductors): 10th of every month — for businesses that deduct TDS on GST under Section 51
- GSTR-8 (TCS by e-commerce operators): 10th of every month — for e-commerce operators collecting TCS under Section 52
- GSTR-5 (Non-resident taxable person): 13th of every month — for foreign businesses registered under GST
- GSTR-6 (Input Service Distributor): 13th of every month — for businesses distributing input tax credit to their branches
- GSTR-11 (UIN holders — embassies, international organisations): 28th of the month following each quarter
- GSTR-10 (Final Return): Within 3 months of cancellation of GST registration — for businesses whose registration has been cancelled
Late Filing Fees for GST Returns
Understanding late fees helps you communicate urgency to clients who are slow to provide documents. The fees are significant enough to motivate timely filing:
- GSTR-1 late fee: Rs 50 per day (Rs 25 CGST + Rs 25 SGST), maximum Rs 10,000 for regular returns | Rs 20 per day for NIL returns
- GSTR-3B late fee: Rs 50 per day (Rs 25 CGST + Rs 25 SGST) for regular returns | Rs 20 per day for NIL returns, maximum Rs 10,000
- GSTR-9 and GSTR-9C late fee: Rs 200 per day (Rs 100 CGST + Rs 100 SGST), subject to a maximum of 0.25% of turnover in the state
- Interest on late payment of GST: 18% per annum on the unpaid tax amount under Section 50 of the CGST Act
- Additional penalty under Section 122: Up to Rs 10,000 or the amount of tax evaded (whichever is higher) for intentional defaults
Tips for Managing GST Compliance Across Multiple Clients
- Start preparing data collection from clients by the 5th of every month — do not wait until the 10th or 11th
- Chase missing purchase invoices and input credit details before the 10th so GSTR-1 reconciliation can be completed on time
- Use a practice management system to track filing status per client — which clients are filed, which are pending, which have issues
- Assign each client's GST work to a dedicated team member with clear responsibility — do not share tasks across multiple people without clarity
- Set reminders 7 days before each due date, not just 1 day — last-minute reminders leave no time to solve problems
- Reconcile GSTR-2B with purchase records monthly, not just at year end — annual reconciliation issues are much harder to fix
How CATeam Helps CA Firms Manage GST Compliance
CATeam pre-loads all GST due dates for every client automatically. When you mark a client as a GST filer with their filing frequency (monthly or QRMP), CATeam creates recurring tasks for GSTR-1, GSTR-3B and all other applicable returns — with the correct due dates based on their turnover category and state. The team is assigned automatically, reminders go out 7 days and 2 days before each deadline, and the filing status for every client is visible at a glance on the dashboard.
GST compliance is manageable when you have the right system and a clear calendar. Bookmark this page and share it with your team. And if you want to go from manually tracking all of this to having it all managed automatically for every client — that is exactly what CATeam is built for.