GST Compliance Calendar for 2026 (Updated) -Deadlines & Filings Checklist

India’s GST framework crossed a critical enforcement threshold on 1st January 2026. The portal now auto-enforces late fees, permanently blocks overdue returns, validates ledger conditions before allowing filings, and flags mismatches using AI-powered cross-referencing across returns, e-invoices, e-way bills, and income tax data. Non-compliance no longer just attracts penalties. It can mean permanent loss of Input Tax Credit (ITC), suspension of GST registration, blocked e-way bill generation, and irreversible gaps in return history. Treelife has worked with 500+ businesses on GST structuring, registration, and compliance, and the 2026 cycle is categorically different from anything that preceded it. This article covers every due date, every new rule, and every enforcement trigger you need to track for FY 2026-27.

How GST filing frequency works in 2026

Your filing obligations in 2026 depend on three variables: your Aggregate Annual Turnover (AATO), the scheme you are registered under, and the state where your principal place of business is located.

Businesses with AATO above ₹5 crore file GSTR-1 monthly by the 11th and GSTR-3B monthly by the 20th. They are also subject to mandatory e-invoicing, 6-digit HSN codes, and GSTR-9C reconciliation.

Businesses with AATO up to ₹5 crore can opt for the QRMP (Quarterly Return Monthly Payment) scheme. Under QRMP, GSTR-1 is filed quarterly (by the 13th of the month after the quarter ends), but tax is paid monthly via the PMT-06 challan for the first two months of each quarter. GSTR-3B is filed quarterly, with a due date split by geography: Group 1 states file by the 22nd and Group 2 states by the 24th of the month following the quarter.

QRMP Group 1 states and UTs: Chhattisgarh, Madhya Pradesh, Gujarat, Maharashtra, Karnataka, Goa, Kerala, Tamil Nadu, Telangana, Andhra Pradesh, Daman and Diu, Dadra and Nagar Haveli, Puducherry, Andaman and Nicobar Islands, Lakshadweep.

QRMP Group 2 states and UTs: Jammu and Kashmir, Himachal Pradesh, Punjab, Uttarakhand, Haryana, Rajasthan, Delhi, Uttar Pradesh, Bihar, Sikkim, Arunachal Pradesh, Nagaland, Manipur, Mizoram, Tripura, Meghalaya, Assam, West Bengal, Jharkhand, Odisha, Chandigarh, Ladakh.

Composition dealers operate on a different track entirely: quarterly CMP-08 statements by the 18th of the month following each quarter, and a single annual GSTR-4 by 30th April.

15 changes in 2026 that every GST-registered business must act on

1. 3-year return filing hard block (effective December 2025)

The GST portal permanently blocks filing any return that is more than three years past its original due date. Returns from FY 2021-22 or earlier that were not filed cannot be filed at all. The window is permanently closed. If your business has any unfiled returns from 2021-22, ITC for those periods is permanently lost, and the compliance gap cannot be rectified. This is not a soft warning. It is a system-level hard block.

2. E-invoicing threshold lowered to ₹5 crore

Mandatory e-invoicing now applies to all businesses with AATO of ₹5 crore or more, reduced from ₹10 crore. Affected businesses must generate invoices through the Invoice Registration Portal (IRP), receive a unique Invoice Reference Number (IRN), and comply with the 30-day reporting window. Invoices older than 30 days cannot be registered. Buyers cannot claim ITC on invoices without a valid IRN.

3. Invoice Management System (IMS) fully active from 2026

IMS is a mandatory compliance layer on the GST portal. Suppliers upload invoices via GSTR-1, IFF, or GSTR-1A. These immediately appear on the recipient’s IMS dashboard. Recipients must Accept, Reject, or mark as Pending each invoice before their GSTR-3B filing date. Draft GSTR-2B is auto-generated on the 14th of each month. Inaction equals deemed acceptance. Pending invoices can only be held for one tax period.

4. New GSTR-1A form for supplier amendments

Suppliers can now amend filed GSTR-1 invoices through a new form, GSTR-1A, before filing GSTR-3B for the same period. This allows corrections to flow through IMS to the recipient’s GSTR-2B. This form did not exist before 2025 and represents a significant change in the amendment workflow.

5. Automatic late fee calculation for annual returns

From 2026, filing GSTR-9 or GSTR-9C late triggers instant, automated late fee calculation by the portal based on the filer’s turnover slab. Larger businesses face proportionately higher fees. The 31st December deadline must be treated as a hard deadline.

6. GST slab rationalisation

The GST rate structure has been rationalised. The standard slabs are now 0%, 5%, 18%, and 40%. The 12% and 28% slabs have been removed for most goods and services. All businesses must update their billing systems, HSN-rate mappings, and price lists to reflect the correct rates from the applicable effective dates. Misclassification under old slabs creates ITC reversal risk during assessments.

7. Stricter ITC matching with near-complete supplier match required

The provisional ITC allowance (previously 5% of matched ITC) has been further restricted. ITC claims must now nearly completely match supplier-filed GSTR-1 data. If your supplier has not filed GSTR-1, you cannot claim ITC on those purchases. Supplier compliance tracking is now a business-critical function, not a back-office task.

8. Mandatory Multi-Factor Authentication (MFA) on the GST portal

MFA is now mandatory for all GST portal logins. Businesses must make sure all authorised signatories and GST practitioners are set up with MFA to avoid disruption to return filing.

9. Mandatory bank account verification

GST registrations without updated and verified bank account details are subject to automatic suspension. During suspension, return filing and e-way bill generation are not possible.

10. Expanded Reverse Charge Mechanism (RCM)

RCM has been expanded to cover additional categories of goods and services. The portal now blocks GSTR-3B submission if any unpaid RCM liabilities or negative credit ledger balances are detected. These must be cleared before filing.

11. GST treatment for cryptocurrency and digital assets

Cryptocurrency exchange commissions and service charges attract 18% GST from 2026. The exchange must register under GST, file returns, and implement e-invoicing if its AATO crosses ₹5 crore. The underlying asset transfer is treated as a supply of goods on Indian exchanges.

12. Clarified GST rules for digital services (SaaS, cloud, AI tools)

Updated guidelines clarify the place of supply for subscription-based software, cloud computing, data analytics, and AI-powered tools. B2B digital services follow the recipient’s location; B2C digital services follow the consumer’s location. Businesses in these sectors must review their IGST versus CGST plus SGST classification.

13. Budget 2026: refund and procedural clarity

Budget 2026 implemented changes from the 56th GST Council Meeting. The minimum refund threshold for exports with GST payment has been removed, so refunds are processed regardless of amount. Provisional refunds have been introduced for inverted duty structures. Valuation rules for post-sale discounts have been clarified, reducing litigation.

14. AATO reassessment obligation

Businesses must reassess their AATO at the start of 2026. Crossing registration or e-invoicing thresholds creates immediate mandatory obligations even if they were not applicable in earlier years.

15. 6-digit HSN code mandatory for higher turnover filers

AATO	HSN digits required
Up to ₹1.5 crore	2-digit HSN
₹1.5 crore to ₹5 crore	4-digit HSN
Above ₹5 crore	6-digit HSN

Complete GST compliance calendar for FY 2026-27 (month by month)

Table 1: Monthly due date master calendar TY 2026-27

Month	Return / Task	Period	Deadline	Filer type
April 2026	GSTR-7 (TDS)	March 2026	10/04/2026	TDS deductors
April 2026	GSTR-8 (TCS)	March 2026	10/04/2026	E-commerce operators
April 2026	GSTR-1 Monthly	March 2026	11/04/2026	Monthly filers
April 2026	GSTR-1 Quarterly (Jan-Mar 2026)	Q4 FY26	13/04/2026	QRMP
April 2026	GSTR-5	March 2026	13/04/2026	Non-resident taxable persons
April 2026	GSTR-6 (ISD)	March 2026	13/04/2026	Input Service Distributors
April 2026	GSTR-3B Monthly	March 2026	20/04/2026	Monthly filers (AATO > ₹5 Cr)
April 2026	GSTR-5A (OIDAR)	March 2026	20/04/2026	OIDAR providers
April 2026	GSTR-3B Q4 Group 1	Q4 FY26	22/04/2026	QRMP Group 1 states
April 2026	GSTR-3B Q4 Group 2	Q4 FY26	24/04/2026	QRMP Group 2 states
April 2026	PMT-06 Month 1	April 2026	25/04/2026	QRMP filers
April 2026	ITC-04	Oct 2025 to Mar 2026	25/04/2026	Manufacturers (job work)
April 2026	GSTR-4	FY 2025-26	30/04/2026	Composition dealers
May 2026	GSTR-7	April 2026	10/05/2026	TDS deductors
May 2026	GSTR-8	April 2026	10/05/2026	E-commerce operators
May 2026	GSTR-1 Monthly	April 2026	11/05/2026	Monthly filers
May 2026	GSTR-1 IFF (optional)	April 2026	13/05/2026	QRMP (M1 of Q1)
May 2026	GSTR-5	April 2026	13/05/2026	Non-resident taxable persons
May 2026	GSTR-6	April 2026	13/05/2026	ISDs
May 2026	GSTR-3B Monthly	April 2026	20/05/2026	Monthly filers
May 2026	GSTR-5A	April 2026	20/05/2026	OIDAR providers
May 2026	PMT-06 Month 1 (Q1)	May 2026	25/05/2026	QRMP filers
June 2026	GSTR-7	May 2026	10/06/2026	TDS deductors
June 2026	GSTR-8	May 2026	10/06/2026	E-commerce operators
June 2026	GSTR-1 Monthly	May 2026	11/06/2026	Monthly filers
June 2026	GSTR-1 IFF (optional)	May 2026	13/06/2026	QRMP (M2 of Q1)
June 2026	GSTR-5	May 2026	13/06/2026	Non-resident taxable persons
June 2026	GSTR-6	May 2026	13/06/2026	ISDs
June 2026	GSTR-3B Monthly	May 2026	20/06/2026	Monthly filers
June 2026	GSTR-5A	May 2026	20/06/2026	OIDAR providers
June 2026	PMT-06 Month 2 (Q1)	June 2026	25/06/2026	QRMP filers
July 2026	CMP-08 Q1	Apr to Jun 2026	18/07/2026	Composition dealers
July 2026	GSTR-7	June 2026	10/07/2026	TDS deductors
July 2026	GSTR-8	June 2026	10/07/2026	E-commerce operators
July 2026	GSTR-1 Monthly	June 2026	11/07/2026	Monthly filers
July 2026	GSTR-1 Quarterly (Q1)	Apr to Jun 2026	13/07/2026	QRMP
July 2026	GSTR-5	June 2026	13/07/2026	Non-resident taxable persons
July 2026	GSTR-6	June 2026	13/07/2026	ISDs
July 2026	GSTR-3B Monthly	June 2026	20/07/2026	Monthly filers
July 2026	GSTR-3B Q1 Group 1	Q1 FY27	22/07/2026	QRMP Group 1 states
July 2026	GSTR-3B Q1 Group 2	Q1 FY27	24/07/2026	QRMP Group 2 states
August 2026	GSTR-7	July 2026	10/08/2026	TDS deductors
August 2026	GSTR-8	July 2026	10/08/2026	E-commerce operators
August 2026	GSTR-1 Monthly	July 2026	11/08/2026	Monthly filers
August 2026	GSTR-1 IFF (optional)	July 2026	13/08/2026	QRMP (M1 of Q2)
August 2026	GSTR-5	July 2026	13/08/2026	Non-resident taxable persons
August 2026	GSTR-6	July 2026	13/08/2026	ISDs
August 2026	GSTR-3B Monthly	July 2026	20/08/2026	Monthly filers
August 2026	PMT-06 Month 1 (Q2)	August 2026	25/08/2026	QRMP filers
September 2026	GSTR-7	August 2026	10/09/2026	TDS deductors
September 2026	GSTR-8	August 2026	10/09/2026	E-commerce operators
September 2026	GSTR-1 Monthly	August 2026	11/09/2026	Monthly filers
September 2026	GSTR-1 IFF (optional)	August 2026	13/09/2026	QRMP (M2 of Q2)
September 2026	GSTR-5	August 2026	13/09/2026	Non-resident taxable persons
September 2026	GSTR-6	August 2026	13/09/2026	ISDs
September 2026	GSTR-3B Monthly	August 2026	20/09/2026	Monthly filers
September 2026	PMT-06 Month 2 (Q2)	September 2026	25/09/2026	QRMP filers
October 2026	CMP-08 Q2	Jul to Sep 2026	18/10/2026	Composition dealers
October 2026	GSTR-7	September 2026	10/10/2026	TDS deductors
October 2026	GSTR-8	September 2026	10/10/2026	E-commerce operators
October 2026	GSTR-1 Monthly	September 2026	11/10/2026	Monthly filers
October 2026	GSTR-1 Quarterly (Q2)	Jul to Sep 2026	13/10/2026	QRMP
October 2026	GSTR-5	September 2026	13/10/2026	Non-resident taxable persons
October 2026	GSTR-6	September 2026	13/10/2026	ISDs
October 2026	GSTR-3B Monthly	September 2026	20/10/2026	Monthly filers
October 2026	GSTR-3B Q2 Group 1	Q2 FY27	22/10/2026	QRMP Group 1 states
October 2026	GSTR-3B Q2 Group 2	Q2 FY27	24/10/2026	QRMP Group 2 states
October 2026	ITC-04 (half-yearly)	Apr to Sep 2026	25/10/2026	Manufacturers (AATO > ₹5 Cr)
November 2026	GSTR-7	October 2026	10/11/2026	TDS deductors
November 2026	GSTR-8	October 2026	10/11/2026	E-commerce operators
November 2026	GSTR-1 Monthly	October 2026	11/11/2026	Monthly filers
November 2026	GSTR-1 IFF (optional)	October 2026	13/11/2026	QRMP (M1 of Q3)
November 2026	GSTR-5	October 2026	13/11/2026	Non-resident taxable persons
November 2026	GSTR-6	October 2026	13/11/2026	ISDs
November 2026	GSTR-3B Monthly	October 2026	20/11/2026	Monthly filers
November 2026	PMT-06 Month 1 (Q3)	November 2026	25/11/2026	QRMP filers
December 2026	GSTR-7	November 2026	10/12/2026	TDS deductors
December 2026	GSTR-8	November 2026	10/12/2026	E-commerce operators
December 2026	GSTR-1 Monthly	November 2026	11/12/2026	Monthly filers
December 2026	GSTR-1 IFF (optional)	November 2026	13/12/2026	QRMP (M2 of Q3)
December 2026	GSTR-5	November 2026	13/12/2026	Non-resident taxable persons
December 2026	GSTR-6	November 2026	13/12/2026	ISDs
December 2026	GSTR-3B Monthly	November 2026	20/12/2026	Monthly filers
December 2026	PMT-06 Month 2 (Q3)	December 2026	25/12/2026	QRMP filers
December 2026	GSTR-9 Annual Return	FY 2025-26	31/12/2026	All regular taxpayers
December 2026	GSTR-9C Reconciliation	FY 2025-26	31/12/2026	AATO > ₹5 Cr
January 2027	CMP-08 Q3	Oct to Dec 2026	18/01/2027	Composition dealers
January 2027	GSTR-7	December 2026	10/01/2027	TDS deductors
January 2027	GSTR-8	December 2026	10/01/2027	E-commerce operators
January 2027	GSTR-1 Monthly	December 2026	11/01/2027	Monthly filers
January 2027	GSTR-1 Quarterly (Q3)	Oct to Dec 2026	13/01/2027	QRMP
January 2027	GSTR-5	December 2026	13/01/2027	Non-resident taxable persons
January 2027	GSTR-6	December 2026	13/01/2027	ISDs
January 2027	GSTR-3B Monthly	December 2026	20/01/2027	Monthly filers
January 2027	GSTR-3B Q3 Group 1	Q3 FY27	22/01/2027	QRMP Group 1 states
January 2027	GSTR-3B Q3 Group 2	Q3 FY27	24/01/2027	QRMP Group 2 states
February 2027	GSTR-7	January 2027	10/02/2027	TDS deductors
February 2027	GSTR-8	January 2027	10/02/2027	E-commerce operators
February 2027	GSTR-1 Monthly	January 2027	11/02/2027	Monthly filers
February 2027	GSTR-1 IFF (optional)	January 2027	13/02/2027	QRMP (M1 of Q4)
February 2027	GSTR-5	January 2027	13/02/2027	Non-resident taxable persons
February 2027	GSTR-6	January 2027	13/02/2027	ISDs
February 2027	GSTR-3B Monthly	January 2027	20/02/2027	Monthly filers
February 2027	PMT-06 Month 1 (Q4)	February 2027	25/02/2027	QRMP filers
March 2027	GSTR-7	February 2027	10/03/2027	TDS deductors
March 2027	GSTR-8	February 2027	10/03/2027	E-commerce operators
March 2027	GSTR-1 Monthly	February 2027	11/03/2027	Monthly filers
March 2027	GSTR-1 IFF (optional)	February 2027	13/03/2027	QRMP (M2 of Q4)
March 2027	GSTR-5	February 2027	13/03/2027	Non-resident taxable persons
March 2027	GSTR-6	February 2027	13/03/2027	ISDs
March 2027	GSTR-3B Monthly	February 2027	20/03/2027	Monthly filers
March 2027	PMT-06 Month 2 (Q4)	March 2027	25/03/2027	QRMP filers
March 2027	RFD-11 (LUT renewal)	FY 2027-28	31/03/2027	GST-registered exporters
March 2027	FY end reconciliation	FY 2026-27	31/03/2027	All taxpayers
April 2027	GSTR-1 Quarterly (Q4)	Jan to Mar 2027	13/04/2027	QRMP
April 2027	GSTR-3B Monthly	March 2027	20/04/2027	Monthly filers
April 2027	GSTR-3B Q4 Group 1	Q4 FY27	22/04/2027	QRMP Group 1 states
April 2027	GSTR-3B Q4 Group 2	Q4 FY27	24/04/2027	QRMP Group 2 states
April 2027	PMT-06 Month 3	April 2027	25/04/2027	QRMP filers
April 2027	ITC-04 (half-yearly)	Oct 2026 to Mar 2027	25/04/2027	Manufacturers (AATO > ₹5 Cr)
April 2027	GSTR-4	FY 2026-27	30/04/2027	Composition dealers
October 2027	ITC-04 (half-yearly)	Apr to Sep 2027	25/10/2027	Manufacturers (AATO > ₹5 Cr)
December 2027	GSTR-9 Annual Return	FY 2026-27	31/12/2027	All regular taxpayers
December 2027	GSTR-9C Reconciliation	FY 2026-27	31/12/2027	AATO > ₹5 Cr

All GST returns: who files what in 2026

Table 2: GST return master reference

Return	Who files	Frequency	Due date	2026 status
GSTR-1	Regular taxpayers (outward supplies)	Monthly (11th) or Quarterly (13th)	11th or 13th	Auto-populated via e-invoice for eligible businesses
GSTR-1A	Suppliers amending filed GSTR-1 invoices	As needed	Before GSTR-3B of same period	New form from 2025
IFF	QRMP taxpayers uploading invoices for M1 and M2	Monthly (M1, M2 of quarter)	13th of month	Optional but recommended
GSTR-2B	Auto-generated ITC statement for recipients	Monthly or Quarterly	Available by 14th of following month	Enhanced via IMS
GSTR-3B	All regular taxpayers (tax payment summary)	Monthly (20th) or Quarterly (22nd/24th)	20th or 22nd/24th	Portal blocks if RCM liabilities unpaid
PMT-06	QRMP taxpayers (monthly tax payment for M1 and M2)	Monthly	25th of month	QRMP scheme
GSTR-4	Composition dealers (annual)	Annual	30th April	Ongoing
CMP-08	Composition dealers (quarterly tax statement)	Quarterly	18th of month after quarter end	Ongoing
GSTR-5	Non-resident taxable persons	Monthly	20th or within 7 days of expiry	Ongoing
GSTR-5A	OIDAR service providers (cross-border digital services to Indian consumers)	Monthly	20th	Ongoing
GSTR-6	Input Service Distributors	Monthly	13th	Ongoing
GSTR-7	TDS deductors under GST	Monthly	10th	Ongoing
GSTR-8	E-commerce operators (TCS)	Monthly	10th	Ongoing
GSTR-9	All regular taxpayers (annual summary)	Annual	31st December	Automated late fee from 2026
GSTR-9C	Taxpayers with AATO above ₹5 crore	Annual	31st December	Self-certified reconciliation
GSTR-11	UIN holders (embassies, diplomatic missions, UN bodies) claiming GST refund on inward supplies	Monthly	28th of following month	Ongoing
ITC-04	Manufacturers (AATO > ₹5 Cr) reporting goods sent to or received from job workers	Half-yearly	25th October and 25th April	For AATO above ₹5 Cr
RFD-11 (LUT)	GST-registered exporters making zero-rated supplies without IGST payment	Annual	31st March (before FY start)	Annual renewal required

Understanding the Invoice Management System (IMS)

IMS is not optional. It is the mechanism by which your GSTR-2B is constructed and by which ITC flows or does not flow to your books. Every regular taxpayer needs to understand how it works before every GSTR-3B filing.

When a supplier files their GSTR-1 or IFF or GSTR-1A, the invoices immediately appear on the recipient’s IMS dashboard. The recipient has three choices: Accept, Reject, or mark as Pending. Draft GSTR-2B is generated on the 14th of each month based on the actions taken by that point. If any action is taken after the 14th, GSTR-2B must be recomputed before GSTR-3B is filed.

The inaction rule is the one most businesses get wrong. If you do not take any action on an invoice in your IMS dashboard, it is automatically treated as accepted and included in your GSTR-2B. This means you are claiming ITC on it whether you intended to or not. If the invoice is incorrect and you later discover the error, reversing it creates a compliance trail and potential interest liability.

Pending invoices cannot be held indefinitely. Monthly filers can hold a pending invoice for one month. QRMP filers can hold for one quarter. After that, the invoice is auto-accepted.

When you reject an invoice, the supplier’s liability for that period increases. The supplier must then amend the invoice via GSTR-1A or issue a fresh invoice. The corrected version appears in your GSTR-2B for the following month.

The practical implication: reconcile your purchase register against IMS every month before the 14th. Do not wait for GSTR-2B to be generated to discover mismatches.

E-invoicing compliance in 2026: what the ₹5 crore threshold means for your business

E-invoicing is mandatory for businesses with AATO of ₹5 crore or more. If your business crossed this threshold in FY 2024-25 or FY 2025-26, you are now subject to this requirement.

All B2B invoices, export invoices, and supplies to SEZ units must be registered on the IRP. The IRP assigns a unique IRN and QR code to each validated invoice. The 30-day reporting window is a hard constraint. Invoices older than 30 days cannot be registered on the IRP. This means you cannot batch-generate IRNs at month end for invoices raised throughout the month. Each invoice must be registered within 30 days of its date.

E-invoices auto-populate GSTR-1. Businesses with e-invoicing do not need to manually enter the same invoice data into GSTR-1. This reduces errors and reconciliation gaps. Non-compliant invoices (those without an IRN) are treated as invalid. Buyers cannot claim ITC on them, which creates a downstream credit disruption that your customers will hold you accountable for.

The following categories are exempt from e-invoicing even above the ₹5 crore threshold: banks, financial institutions, insurance companies, SEZ units (as suppliers), and goods transport agencies.

What the new GST rate slabs mean for your invoices and systems

The 2026 rate rationalisation removes the 12% and 28% slabs for most goods and services and consolidates the structure into four tiers: 0%, 5%, 18%, and 40%. The 40% slab applies to goods previously in the 28% bracket where the Council has determined a higher rate is appropriate.

This is not an academic change. If your ERP or billing software still has HSN codes mapped to 12% or 28%, every invoice you generate is wrong. Wrong rate on invoice means wrong ITC for your buyer, potential mismatch in GSTR-2B, and exposure during assessment. The correction sequence is: update HSN-rate mapping in your billing system, re-issue corrected invoices where the old rate was applied, and file GSTR-1A for any amendments required for already-filed returns.

Check the GST portal’s rate notification history at www.gst.gov.in for the exact effective dates by HSN code. Do not rely on third-party summaries for this.

How does the 3-year hard block affect businesses with unfiled returns?

The 3-year filing hard block is the most consequential change for businesses with compliance backlogs. As of December 2025, the portal permanently blocks any return that is more than three years past its original due date. The word “permanently” is accurate. There is no application, no late fee payment, and no tribunal order that can reopen it.

For FY 2021-22 returns: the window closed in December 2025. Nothing can be done.

For FY 2022-23 returns: the window will close in December 2026. If you have any unfiled GSTR-1, GSTR-3B, GSTR-9, or CMP-08 for FY 2022-23, file them before December 2026 with applicable late fees, even if ITC is partially or fully lost.

For FY 2023-24 returns: the window closes in December 2027.

The downstream effect of an unfiled return is not just the period itself. It creates a permanent gap in the GSTR-2B of every customer who bought from you in that period. Their ITC claims for those invoices remain unmatched indefinitely, creating assessment risk for them. This is why customers are increasingly asking suppliers for GSTR-1 filing confirmations before processing invoices.

Related: Treelife’s Annual Compliance calendar services for startups

Penalties and enforcement in 2026: what the portal does automatically

The penalty framework for GST in 2026 is largely automated. Understanding what the portal can do without any manual intervention from a tax officer is critical.

Table 3: Penalty and enforcement triggers

Trigger	Consequence	Automated?
Late filing of GSTR-1, GSTR-3B, GSTR-9	₹50 per day (₹20 per day for nil returns), subject to turnover-based caps	Yes
Late filing of GSTR-9 / GSTR-9C	Automated late fee calculation by portal, proportional to turnover slab	Yes from 2026
Return more than 3 years overdue	Permanent block on filing	Yes from Dec 2025
Unmatched ITC (supplier GSTR-1 not filed)	ITC denied	Yes
Missing or unverified bank account	Automatic GST registration suspension	Yes
Unpaid RCM liability	GSTR-3B filing blocked	Yes
Negative credit ledger balance	GSTR-3B filing blocked	Yes
GST registration suspension	E-way bill generation blocked	Yes
IMS mismatch	ITC reversal risk, potential scrutiny	Partially automated
E-invoice non-compliance (no IRN)	Invoice treated as invalid, buyer ITC denied	Yes

The implications of a suspended registration are severe. A suspended GSTIN cannot file returns, cannot generate e-way bills, and cannot receive or pass ITC. If you are a vendor to a large corporate or an e-commerce platform, suspension will almost certainly trigger contract termination or payment holds.

GST compliance checklist for FY 2026-27

Registration and setup (annual, review at start of FY)

• Verify GSTIN status on portal. Confirm no suspension flags.
• Update and verify bank account linked to GSTIN.
• Confirm AATO for previous FY. Check if e-invoicing threshold (₹5 crore) has been crossed.
• Confirm filing frequency (monthly or QRMP). Opt in or out of QRMP by the last date of the preceding quarter.
• Verify MFA is enabled for all authorised signatories.
• Update HSN/SAC codes and rate mappings in billing system to reflect 2026 rate slabs.
• File RFD-11 (LUT) by 31st March if you export without IGST payment.

Monthly compliance (before GSTR-3B due date)

• Reconcile sales register against GSTR-1 already filed.
• Review IMS dashboard. Accept, Reject, or mark as Pending all supplier invoices before the 14th.
• Verify GSTR-2B once generated. Cross-check against purchase register.
• Identify and follow up with suppliers whose GSTR-1 is not filed (ITC at risk).
• Clear all RCM liabilities. Verify no negative credit ledger balance before filing GSTR-3B.
• File GSTR-1 by 11th (monthly filers) or IFF by 13th (QRMP M1/M2).
• File GSTR-3B by 20th (monthly) or 22nd/24th (QRMP).
• For QRMP filers: pay PMT-06 challan by 25th for M1 and M2.

Invoicing and e-invoice compliance (ongoing)

• Generate IRN for all B2B invoices, export invoices, and SEZ supplies within 30 days.
• Include QR code on all e-invoices.
• Report 6-digit HSN/SAC codes on all invoices (AATO above ₹5 crore) or 4-digit codes (₹1.5 crore to ₹5 crore).
• Verify invoice numbering is sequential.
• For RCM transactions: raise self-invoice where required.

Quarterly compliance (after each quarter)

• File GSTR-1 for the full quarter by the 13th of the following month (QRMP filers).
• File CMP-08 by 18th of the month after the quarter (composition dealers).
• Reconcile GSTR-2B for the full quarter against books.
• Review e-way bill compliance for all consignments above ₹50,000.

Annual compliance

1. Reconcile all GSTR-2B data against purchase register for full FY before March year-end.
2. Identify ITC reversals required: Rule 42 (mixed-use inputs), Rule 43 (capital goods), Section 17(5) (blocked credits).
3. File GSTR-9 by 31st December.
4. File GSTR-9C (self-certified reconciliation) by 31st December if AATO above ₹5 crore.
5. File GSTR-4 by 30th April (composition dealers, for previous FY).
6. File RFD-11 (Letter of Undertaking) by 31st March each year if you export without IGST payment (for the following FY).
7. Check and clear any backlog returns before the 3-year hard block closes the window.
8. Maintain all GST records (sales, purchases, tax payments, ITC, e-invoices, e-way bills, IMS data) for a minimum of 6 years.

GST for digital businesses: SaaS, cloud, and AI tools

The 2026 guidelines resolve a longstanding ambiguity for Indian SaaS companies and digital service providers on the place of supply and applicable tax.

For B2B digital services (one GST-registered entity selling to another GST-registered entity), the place of supply is the recipient’s registered address. If the recipient is in Maharashtra and you are in Karnataka, the supply is inter-state and IGST applies.

For B2C digital services (selling to a consumer without a GSTIN), the place of supply is the consumer’s location. This is determined by their billing address, delivery address, or IP address, in that order of preference. If the consumer is in Gujarat, CGST plus SGST applies and must be remitted to Gujarat.

SaaS businesses selling across states on a B2C basis face a compliance obligation in every state where consumers are located, unless they are covered by a single GSTIN for IGST purposes. Review your IGST versus CGST plus SGST split carefully. Incorrect classification means incorrect ITC flows for your B2B customers and potential demand notices.

OIDAR providers and GSTR-5A: GST for cross-border digital services

Online Information and Database Access or Retrieval (OIDAR) services cover a specific category: digital services delivered over the internet with minimal human intervention, where delivery is essentially automated. This includes cloud-based software access, e-books, online gaming, digital advertising, and database access services supplied to non-business recipients in India by a foreign provider.

If you are a foreign company providing such services to consumers in India (B2C), you are required to register under GST in India under Section 14 of the IGST Act, even without a physical presence here. You file GSTR-5A monthly, by the 20th of the following month, reporting all B2C OIDAR supplies made to Indian recipients and paying 18% IGST.

If you are an Indian platform aggregating or reselling OIDAR services from foreign providers to Indian consumers, the Indian entity bears the GST liability as the recipient of the foreign service and must account for it under the reverse charge mechanism. Review your platform structure carefully if you are in this category. The place of supply for B2C OIDAR is the consumer’s location in India, which governs whether IGST or state-split CGST plus SGST applies.

ITC-04: job work compliance for manufacturers

ITC-04 is a half-yearly return filed by manufacturers who send goods to job workers for processing, repair, or testing. It applies to businesses with AATO above ₹5 crore.

The return captures a summary of goods sent to job workers and goods received back, by HSN code and quantity. It is filed twice a year: for the April to September half-year by 25th October, and for the October to March half-year by 25th April of the following year.

The compliance risk here is specific. If goods sent to a job worker are not received back within one year (two years for capital goods), the supply is treated as a deemed supply from the manufacturer and GST becomes payable. ITC-04 is the mechanism by which the tax department tracks this timeline. Manufacturers who miss ITC-04 filings face penalties under Section 125 of the CGST Act and create audit flags on their job work movement records. If you use third-party vendors for manufacturing, packaging, or component assembly, verify whether your arrangement qualifies as job work and whether ITC-04 applies.

Table 4: ITC-04 due dates for FY 2026-27

Period	Due date
April 2026 to September 2026	25/10/2026
October 2026 to March 2027	25/04/2027

RFD-11 (Letter of Undertaking): exporters filing without IGST payment

Any GST-registered exporter who wants to export goods or services without paying IGST upfront must file Form RFD-11, the Letter of Undertaking (LUT), at the beginning of each financial year. Without a valid LUT, you must pay IGST on export invoices and then claim a refund, which ties up working capital for the refund processing period.

The LUT is filed online on the GST portal and is valid for the full financial year. For FY 2026-27, the LUT should have been filed before 1st April 2026. If you missed it, you can file a late LUT and claim a refund of IGST paid on exports in the interim. The reference number generated on LUT filing must be quoted on every export invoice and shipping bill.

From Budget 2026, the minimum refund threshold for exports with GST payment has been removed, so even small exporters who chose to pay IGST instead of filing a LUT can now claim full refunds regardless of amount. That said, LUT filing remains the cleaner route operationally since it avoids the refund cycle altogether.

The due date to file RFD-11 for FY 2027-28 is 31st March 2027. Add this to your annual compliance calendar now.

GST treatment for cryptocurrency transactions from 2026

From 2026, the GST treatment of cryptocurrency is clarified as follows. Commissions and service charges earned by cryptocurrency exchanges attract 18% GST. The exchange must register under GST, file returns, and implement e-invoicing if its AATO crosses ₹5 crore. The underlying asset transfer is treated as a supply of goods.

Individual crypto traders do not typically have GST liability on their trading activity unless they are running a business that crosses the GST registration threshold. However, if you operate a platform, facilitate trades, or provide crypto advisory services, review your registration obligation carefully.

Is the QRMP scheme right for your business in FY 2026-27?

The QRMP scheme is available to businesses with AATO up to ₹5 crore in the preceding financial year. It reduces the number of GSTR-1 filings from 12 to 4 per year. GSTR-3B is also filed quarterly rather than monthly. The trade-off is that tax must still be paid monthly via PMT-06 for the first two months of each quarter, and the quarterly GSTR-3B due date (22nd/24th) is later than the monthly date (20th), giving marginal cash flow breathing room.

QRMP is worth considering for businesses with relatively stable monthly revenue, lower supplier volume, and in-house accounting capacity. It is not well-suited to businesses with high-volume B2B transactions, where customers depend on your GSTR-1 data being available early in the month for their own ITC reconciliation. In those cases, opting into IFF (Invoice Furnishing Facility) within QRMP partially addresses the customer ITC visibility problem.

You can opt in or opt out of QRMP on the GST portal by the last date of the preceding quarter. The general rule: opt in or opt out for Q1 (April to June) by 30th April; for Q2 (July to September) by 31st July; for Q3 (October to December) by 31st October; for Q4 (January to March) by 31st January. For Q1 FY 2026-27, the deadline was 30th April 2026. Changes made after these dates apply only from the following quarter.

Frequently asked questions

Q: What is the due date for GSTR-9 for FY 2025-26?
A: 31st December 2026. Automatic late fees apply from 2026. The portal calculates the fee instantly based on your turnover slab. File before this date without exception.

Q: What is the due date for GSTR-9C for FY 2025-26?
A: 31st December 2026, the same as GSTR-9. GSTR-9C applies to taxpayers with AATO above ₹5 crore. It is a self-certified reconciliation statement comparing your audited financials with your GST annual return. You do not need a CA certification; self-certification is accepted.

Q: If my supplier has not filed GSTR-1, can I still claim ITC?
A: No. Under the 2026 stricter ITC matching framework, ITC claims must nearly completely match supplier-filed GSTR-1 data. The 5% provisional ITC buffer has been effectively eliminated. If your supplier has not filed, monitor via IMS and consider placing payment holds until the supplier is current.

Q: What does IMS inaction mean for my GSTR-2B?
A: If you take no action (Accept, Reject, or Pending) on an invoice in your IMS dashboard, it is automatically treated as accepted and included in your GSTR-2B. You effectively claim ITC on it. If the invoice is incorrect or ineligible, you need to reject it before the 14th of the month to keep it out of GSTR-2B.

Q: Does the 30-day e-invoice rule mean I cannot raise a backdated invoice?
A: You can raise a backdated invoice. The 30-day rule applies to IRP registration, not invoice date. The invoice date can be up to 30 days before the registration date. An invoice dated today but not registered on the IRP within 30 days from today cannot be registered at all.

Q: What happens if my GST registration is suspended?
A: During suspension, you cannot file returns, generate e-way bills, or receive ITC. Your customers cannot claim ITC on your invoices during the suspension period. Registration is typically suspended for missing bank details, persistent non-filing, or AATO threshold breach without registration. Suspension can be revoked by completing the required action on the portal.

Q: Is e-invoicing mandatory for B2C sales?
A: No. E-invoicing applies to B2B supplies, export supplies, and supplies to SEZ units. B2C invoices are exempt from IRP registration. However, if you issue a consolidated B2C invoice and later need to amend it to a B2B invoice, the amendment requires IRP registration.

Q: As a composition dealer, do I need to manage IMS?
A: Composition dealers do not claim ITC, so IMS is not directly relevant to their credit position. However, composition dealers who pay RCM on inward supplies should review the expanded RCM categories for 2026 to make sure all applicable liabilities are discharged before the quarterly CMP-08 filing.

Q: My business crossed ₹5 crore AATO in FY 2025-26. When does mandatory e-invoicing apply?
A: Immediately from 1st April 2026. If you crossed the ₹5 crore threshold in FY 2025-26, you are required to generate IRNs for all eligible invoices from the first day of FY 2026-27. There is no grace period.

Q: What is the GST rate on SaaS subscriptions billed to Indian businesses?
A: 18% GST. For B2B SaaS (recipient has a GSTIN), the place of supply is the recipient’s registered state. Apply IGST for inter-state supply and CGST plus SGST for intra-state supply. Make sure your invoices display the recipient’s GSTIN and the correct place of supply.

Q: Can I get a GST refund on exports even for small amounts from 2026?
A: Yes. The minimum refund threshold for exports with GST payment has been removed following Budget 2026 changes from the 56th GST Council Meeting. Refunds are processed regardless of amount.

Q: What is the late fee for GSTR-1?
A: ₹50 per day of delay (₹25 CGST plus ₹25 SGST). For nil returns, the fee is ₹20 per day (₹10 CGST plus ₹10 SGST). The portal calculates this automatically. Caps apply based on turnover.

Q: Do I need to file IFF or is it optional under QRMP?
A: IFF is optional. You are not required to upload invoices for M1 and M2 under QRMP via IFF. However, if your B2B customers depend on early ITC visibility, IFF is strongly recommended. Without IFF, your customers can only see your invoices when you file the quarterly GSTR-1 on the 13th of the month following the quarter end.

Q: What records must I maintain under GST and for how long?
A: All sales invoices, purchase invoices, credit notes, debit notes, e-invoices, e-way bills, IMS actions, tax payment challans, and ITC claim records must be maintained for a minimum of 6 years from the due date of the annual return for that year. GST Section 35 mandates this.

Regulatory references

• Central Goods and Services Tax Act 2017, Sections 10 (composition scheme), 17 (ITC conditions and blocks), 35 (record-keeping), 37 (GSTR-1), 39 (GSTR-3B), 44 (annual return), 47 (late fees), 51 (TDS), 52 (TCS), 125 (general penalty)
• Integrated Goods and Services Tax Act 2017, Section 14 (OIDAR services)
• CGST Rules 2017, Rules 42 and 43 (ITC reversal), Rule 45 (ITC-04 job work), Rule 48 (e-invoicing), Rule 61 (GSTR-3B), Rule 80 (GSTR-9 and 9C), Rule 96A (LUT for zero-rated supplies)
• Notification No. 13/2020-Central Tax dated 21/03/2020 (QRMP scheme)
• 56th GST Council Meeting recommendations (Budget 2026 implementation)
• CBIC Circular on place of supply for digital services (2026)
• GST portal advisory on IMS framework (October 2024 onwards)
• GST portal advisory on 3-year return filing hard block (December 2025)
• CBIC Notification on e-invoicing threshold reduction to ₹5 crore

External sources

• GST Portal: www.gst.gov.in
• CBIC: www.cbic.gov.in
• Invoice Registration Portal: www.einvoice1.gst.gov.in