The first quarter of FY 2026-27 is already behind us, hopefully with your GST returns filed on time and your business running smoothly. Now, it’s turn to shift your focus to the next three quarters.
A well-planned GST calendar can help you stay ahead of deadlines, avoid penalties, and keep your compliance stress-free throughout the year.
Let’s walk through crucial GST due dates, return filing, and compliance requirements you need to know. We recommend Marg GST Billing Software for end-to-end compliance, updates, accurate billing and inventory management.
Why is GST Compliance Essential for Businesses?
GST compliance is not just about filing returns anymore. With increasing digital scrutiny, automated invoice matching, e-invoicing, e-way bills, and real-time reconciliations, even a small mistake can lead to notices, blocked Input Tax Credits, or unnecessary late fees.
The Government of India has announced slab changes and revised regulations in September 2025. You are required to maintain a clear GST calendar and ensure timely compliance for seamless business operations. In this endeavour, a right GST billing software is crucial for trades of all sizes.
Whether you are a retailer, wholesaler, distributor, manufacturer, pharmacist, or supplier, this guide will help you understand;
- Month-wise GST due dates
- Return filing deadlines
- Quarterly compliance requirements
- Annual GST obligations
- Tips to avoid penalties
- How the best GST Billing Software in India simplifies compliance
Why does every business need a GST calendar in FY 2026-27?
Think of your GST calendar as your business’s compliance roadmap. Instead of remembering multiple due dates every month, you know exactly;
- When to file GSTR-1
- When to submit GSTR-3B
- When QRMP returns are due
- When to pay taxes
- When annual returns must be filed
A missed deadline doesn’t just attract late fees, it can also delay Input Tax Credit claims, impact cash flow, and even affect business credibility. That’s why many businesses now rely on billing software that automatically reminds users about upcoming GST deadlines and prepares returns using real-time business data.
Major GST Returns Every Business Must Know in India
| GST Returns | Purpose | Who Files | Due Date |
| GSTR-1 | Outward Supplies (Sales) | Regular Taxpayers | 11th of Next Month(Monthly)/ 13th After Quarter (QRMP) |
| GSTR-3B | Summary Return and Tax Payment | Regular Taxpayers | 20th of Next Month (Monthly)/ 22nd or 24th After Quarter (QRMP) |
| GSTR-4 | Annual Return | Composition Dealers | 30 April Following the Financial Year |
| CMP-08 | Quarterly Tax Payment | Composition Taxpayers | 18th of The Month Following Each Quarter |
| GSTR-09 | Annual GST Returns | Eligible Taxpayers | 31st December Following the FY |
| GSTR-9C | Reconciliation Statement | Applicable Taxpayers | 31st December Following the FY |
Due dates are based on the standard GST filing schedule for FY 2026-27.
GST Calendar FY 2026-27 (April to September’26)
April 2026
| Due Date | GST Compliance |
| 10th April | GSTR-7 and GSTR-8 |
| 11th April | GSTR-1 (March Monthly) |
| 13th April | GSTR-5 & GSTR-6 |
| 20th April | GSTR-3B (March Monthly) |
| 22/24th April | QRMP GSTR-3B (Jan to March Quarter) |
| 25th April | PMT-06 (QRMP) |
| 30th April | GSTR-4 (Composition Annual Return) |
April is one of the busiest GST months because businesses close the previous FY and begin the new Financial Year.
May 2026
| Due Date | Compliance |
| 10th May | GSTR-7 and GSTR-8 |
| 11th May | GSTR-1 (April) |
| 13th May | GSTR-5 and GSTR-6 |
| 20th May | GSTR-3B (April) |
| 25th May | PMT-06 (QRMP) |
Businesses should also reconcile purchase invoices with GSTR-2B before filing GSTR-3B to ensure accurate ITC claims.
June 2026
| Due Date | Compliance |
| 10th June | GSTR-7 and GSTR-8 |
| 11th June | GSTR-1 |
| 13th June | GSTR-5 and GSTR-6 |
| 20th June | GSTR-3B |
| 25th June | PMT-06 |
Businesses should ensure all invoices for the first quarter are properly recorded by June, especially if they plan to file under the QRMP scheme. A right GST billing software helps you with timely notification, compliance as scheduled, and fully regulated.
July 2026
July marks the beginning of the second quarter and brings several quarterly GST filings.
| Due Date | Compliance |
| 10th July | GSTR-7 and GSTR-8 |
| 11th July | GSTR-1 (Monthly) |
| 13th July | Quarterly GSTR-1 (April to June) |
| 18th July | CMP-08 |
| 20th July | GSTR-3B |
| 22/24th July | Quarterly GSTR-3B (QRMP) |
Quarterly GST filers should double-check sales, tax liability, and ITC before submitting returns.
August 2026
| Due Date | Compliance |
| 10th August | GSTR-7 and GSTR-8 |
| 11th August | GSTR-1 |
| 13th August | GSTR-5 and GSTR-6 |
| 20th August | GSTR-3B |
| 25th August | PMT-06 |
This is a good month to review whether your invoice data, GST rates, and HSN/SAC codes are accurate before the festive season begins. For everything related to GST, explore Marg ERP. Call for a free demo and never ever miss another due date.
September 2026
| Due Date | Compliance |
| 10th September | GSTR-7 and GSTR-8 |
| 11th September | GSTR-1 |
| 13th September | GSTR-5 and GSTR-6 |
| 20th September | GSTR-3B |
| 25th September | PMT-06 |
September is often considered a financial checkpoint for the next quarter of the FY. Businesses should reconcile.
Over 10 lakh businesses in India trust Marg GST Billing Software for collection and reconciliation. Marg ERP offers seamless integrated auto-reconciliation with 140 plus banks and connected banking with ICICI Bank, SBI, Axis Bank, J&K Bank, and IndusInd Bank.
Monthly vs Quarterly GST Filing
Many business owners are confused about whether they should file monthly or quarterly. Here’s a simple comparison for your detailed understanding.
| Monthly Filing | QRMP Filing |
| Suitable for larger businesses | Suitable for eligible MSMEs, small and growing businesses |
| GSTR-1 every month | GSTR-1 every quarter |
| GSTR-3B every month | GSTR-3B every quarter |
| Tax paid monthly | Tax paid monthly through PMT-06 |
| Better for businesses with high transaction volume | Reduces compliance workload |
If you are a growing MSME, choosing the best GST billing software can save significant time and effort while keeping compliance manageable.
How GST Billing Software Makes Compliance Easier.
Imagine preparing GST returns manually every month. You wear multiple hats that’s become overwhelming including;
- Match invoices
- Calculate GST
- Verify tax rates
- Generate reports
- Track Input Tax Credit
- File returns
- Correct errors
Advanced GST billing software automates the entire process, saves time and keeps you compliant always, prevents risks of penalty and non-compliance scenarios.
GST Billing Software for Small Businesses can;
- Generate GST-compliant invoices
- Auto-calculate CGST, SGST, IGST, and cess
- Prepare GSTR-1 and GSTR-3B reports
- Track Input Tax Credit
- Manage e-Invoicing and e-Way Bills
- Send filing reminders
- Reconcile purchase and sales data
- Maintain audit-ready records
For over 8.84 crores registered MSMEs of India, using GST Billing Software for Small Businesses significantly reduces manual errors and saves hours every month.
Businesses looking for flexibility can choose GST Billing Software online for anytime, anywhere access, while those preferring desktop operations can opt for GST Billing Software offline free download options (where available) or licensed offline solutions with cloud backup for enhanced security and accessibility.
You can explore Marg ERP for both online cloud-based solution and offline on-site ERP solution.
GST Calendar FY 2026-27 (October’26 to March’27)
While the first half of the financial year is all about staying on track, the second half is where businesses need to focus on reconciliation, tax planning, and preparing for year-end compliance.
Keeping your records updated with a reliable GST Billing Software can make this process much smoother.
October 2026
October begins the third quarter of FY 2026-27 and includes quarterly filing deadlines for businesses under the QRMP scheme.
| Due Date | GST Compliance |
| 10th October | GSTR-7 & GSTR-8 |
| 11th October | GSTR-1 (Monthly Filers) |
| 13th October | GSTR-1 (Quarterly Filers, July to Sep’26) |
| 18th October | CMP-08 (Composition Taxpayers) |
| 20th October | GSTR-3B (Monthly Filers) |
| 22/24 October | GSTR-3B (QRMP Filers) |
| 25th October | PMT-06 |
Reconcile your invoices before filing GSTR-1 to ensure customers receive accurate Input Tax Credit (ITC).
November 2026
| Due Date | GST Compliance |
| 10th November | GSTR-7 and GSTR-8 |
| 11th November | GSTR-1 |
| 13th November | GSTR-5 and GSTR-6 |
| 20th November | GSTR-3B |
| 25th November | PMT-06 |
With the festive season usually resulting in higher sales, November is a good time to review inventory, verify GST classifications, and reconcile high-volume transactions.
December 2026
| Due Date | GST Compliance |
| 10th December | GSTR-7 and GSTR-8 |
| 11th December | GSTR-1 |
| 13th December | GSTR-5 and GSTR-6 |
| 20th December | GSTR-3B |
| 25th December | PMT-06 |
December is also the right time to begin preparing for annual GST reconciliation rather than waiting until the financial year ends.
January 2027
January marks the beginning of the final quarter of FY 2026-27.
| Due Date | GST Compliance |
| 10th January’27 | GSTR-7 and GSTR-8 |
| 11th January’27 | GSTR-1 |
| 13th January’27 | GSTR-1 (Quarterly Filers- Oct. to Dec.) |
| 18th January’27 | CMP-08 |
| 20th January’27 | GSTR-3B |
| 22/24th January’27 | GSTR-3B (QRMP) |
Now is the perfect time to identify pending reconciliations before the FY 2026-27 closes.
February 2027
| Due Date | GST Compliance |
| 10th February’27 | GSTR-7 and GSTR-8 |
| 11th February’27 | GSTR-1 |
| 13th February’27 | GSTR-5 and GSTR-6 |
| 20th February’27 | GSTR-3B |
| 25th February’27 | PMT-06 |
Businesses should verify the following before moving towards the last month of the current financial year.
- Vendor GSTINs
- HSN/SAC Codes
- Tax rates
- Pending ITC claims
- Credit and debit notes
March 2027
March is the last month of the ongoing Financial Year and therefore a very crucial month for every GST-registered business across India.
| Due Date | GST Compliance |
| 10th March’27 | GSTR-7 and GSTR-8 |
| 11th March’27 | GSTR-1 |
| 13th March’27 | GSTR-5 and GSTR-6 |
| 20th March’27 | GSTR-3B |
| 25th March’27 | PMT-06 |
Before the financial year 2026-27 ends, businesses should ensure;
- Books of accounts are updated
- Purchase and sales registers match GST returns
- ITC is correctly claimed
- Tax liabilities are paid
- Pending invoices are uploaded
- Stock records are reconciled
A little effort in March can save hours of corrections and notices later. Let’s explore late fees and interest if you miss the GST due dates. An advanced GST billing software ensures no delays and no due dates misses, call for a demo now.
GST Late Fees and Interest
| Types/Categories | Charges |
| Late Fee | As applicable under GST provisions based on the return type and filing delays. |
| Interest on Tax Liability | 18% per annum on delayed tax payment |
| Wrong ITC Claims | Interest and recovery proceedings, wherever applicable |
| Non-filing of Returns | May lead to notices, restrictions on filing subsequent returns, and cancellation proceedings in prolonged cases |
Delayed GST compliance can also affect ITC availability for customers and vendor relationships along with financial penalties.
What is QRMP Scheme?
The Quarterly Return Monthly Payment (QRMP) Scheme is designed for eligible small taxpayers to reduce compliance burden.
Under QRMP, businesses need to;
- File GSTR-1 quarterly
- File GSTR-3B quarterly
- Taxpayment every month through PMT-06
- Continue issuing regular GST invoices
It is ideal for businesses with lower transaction volumes that still want to remain GST compliant without filing returns every month.
What is the Composition Scheme?
The Composition Scheme is another option available to eligible small taxpayers under GST. Its benefit include;
- Lower tax rates (subject to GST rules)
- Simplified compliance
- Quarterly tax payments through CMP-08
- Annual return in GSTR-4
- Reduced paperwork
However, businesses under this scheme cannot collect GST from customers or claim Input Tax Credit and must comply with the restrictions prescribed under GST law.
What Common GST Filing Mistakes You Should Avoid.
Even experienced businesses make mistakes that can delay compliance. Avoid these common errors for seamless GST filing experience and smoother business operations.
- Filing returns after the due date
- Incorrect GSTIN details
- Wrong HSN/SAC codes
- Claiming excess ITC
- Missing supplier invoices
- Duplicate invoices
- Incorrect GST rates
- Forgetting to reconcile GSTR-2B
- Ignoring amendments
- Maintaining incomplete records
The easiest way to reduce these errors is by using automated Billing Software instead of manual spreadsheets.
We have explored due dates, return filing deadlines, mistakes to remember and avoid, and why you require a quality billing software like Marg ERP. Now, let’s explore the GST compliance checklist in the following section.
GST Compliance Checklist for FY 2026-27
- Generate GST-compliant invoices
- Verify customer and supplier GSTINs
- Match purchase invoices with GSTR-2B
- Reconcile sales register
- Pay GST before the due date
- File GSTR-1
- File GSTR-3B
- Download acknowledgement receipts
- Maintain digital backups
- Review pending notices on the GST portal
Following this simple checklist throughout the year can help you stay audit-ready and avoid last-minute stress.
Why are Businesses choosing GST Billing Software?
GST compliance has evolved beyond generating invoices. Today’s businesses need software that manages billing, accounting, inventory, taxation, and reporting from a single platform.
A modern GST billing software offers;
- GST-compliant billing
- Automatic tax calculations
- e-Invoicing support
- e-Way Bill generation
- Inventory management
- Barcode billing
- Multi-user access
- Real-time dashboards
- Accounting integration
- Purchase and sales reconciliation
- Financial reports
- Data backup and security
Conclusion
With one quarter of FY 2026-27 already behind us, now is the ideal time to review your GST compliance strategy for the remaining three quarters. Mark every due date, reconcile your books regularly, verify your ITC, and file returns on time.
More importantly, don’t let compliance become a monthly headache. The right Billing Software can automate routine GST tasks, minimise filing errors, and give you more time to focus on growing your business.
Whether you are running a small retail shop or managing multiple business locations, staying organised today will help you avoid penalties tomorrow and keep your business compliant throughout FY 2026-27.
FAQs on GST Compliance and Billing Software
What is the due date for GSTR-1?
For monthly filers, GSTR-1 is generally due on the 11th of the following month. Quarterly filers under the QRMP scheme generally file by the 13th after the end of the quarter, subject to applicable notifications.
What happens if I miss a GST filing deadline?
Delayed filing may result in applicable late fees, interest on outstanding tax liabilities, and potential compliance notices.
Is GST Billing Software mandatory?
No. However, using GST-compliant billing software significantly reduces manual work, improves accuracy, and helps businesses stay compliant.
Which businesses should use GST Billing Software?
Any GST-registered business including retailers, wholesalers, distributors, manufacturers, pharmacies, restaurants, and service providers can benefit from GST Billing Software like Marg ERP.
Can GST Billing Software help with e-Invoicing and e-Way Bills?
Yes. Many modern solutions support e-Invoicing, e-Way Bills, GST return preparation, reconciliation, inventory management, and accounting in one platform.
