What Is GST Return Filing?
GST return filing is the periodic submission of sales, purchase, and tax payment data to the government’s GST portal by every registered taxpayer in India. Section 39 of the CGST Act, 2017 makes this mandatory for regular taxpayers. Composition dealers file separately under Section 10.
The thing that bites most SME owners is the dependency chain between returns. When you file GSTR-1 (your outward supply details), the portal picks up those invoices and drops them into your buyer’s GSTR-2B, which is the statement they use to claim input tax credit. If you do not file, their credit is gone. Not reduced. Gone. And on your end, GSTR-3B is where the actual money moves: you declare what you owe, subtract the ITC you are entitled to, and pay the difference. GSTR-9 wraps up the financial year by reconciling the two into one annual statement. Late fees start at Rs.50 a day the moment you miss any of these.
What Are the Main Types of GST Returns?
Three matter for most businesses. The rest are niche.
| Return | Who Files | What It Contains | Due Date |
|---|---|---|---|
| GSTR-1 | Regular taxpayers | B2B invoices, B2C sales, credit/debit notes, exports | 11th of following month |
| GSTR-3B | Regular taxpayers | Summary return with tax payment: output tax, ITC claimed, net payable | 20th of following month |
| GSTR-9 | Turnover > Rs.2 crore | Annual reconciliation of GSTR-1 and GSTR-3B | 31st December of following FY |
| CMP-08 | Composition dealers | Quarterly self-assessed tax payment | 18th of month after quarter |
| GSTR-4 | Composition dealers | Annual return with turnover and tax summary | 30th June of following FY |
If your turnover sits under Rs.5 crore, the QRMP scheme lets you file GSTR-1 and GSTR-3B quarterly. But tax payment is still monthly, due by the 25th via PMT-06. Plenty of business owners in Surat and Rajkot sign up for QRMP thinking it reduces their compliance load, and then get surprised by that monthly challan.
How Does the Monthly Filing Cycle Work?
Say it is April 2026.
You file GSTR-1 by 11th May. Every B2B invoice with buyer GSTINs goes in, along with B2C summaries and credit notes. Leave out an invoice and the buyer cannot claim ITC on that purchase. Their CA calls yours. Happens constantly.
Around the 14th, the portal auto-generates your GSTR-2B. Read-only. Built entirely from what your suppliers reported in their GSTR-1 filings. Here is where money gets wasted: the Invoice Management System (IMS), available since October 2025, lets you accept, reject, or hold supplier invoices before GSTR-2B locks. At Petpooja, we find barely half our Invoice clients bother opening it. Once 2B finalises, fixing a wrong credit means reversing it next month and paying interest. Not worth the laziness.
GSTR-3B wraps up the month, due 20th May. Declare output liability, claim ITC from your 2B, pay net tax. If the portal spots a gap between what you reported in GSTR-1 and what you declared in 3B, it triggers FORM GST ASMT-10. That is a notice. Respond or escalate.
What Are the Late Fees and Penalties?
Rs.50 per day. Rs.25 CGST, Rs.25 SGST. Starts the morning after the due date and does not stop until you file.
| Return | Late Fee Per Day | Cap |
|---|---|---|
| GSTR-1 / GSTR-3B | Rs.50 (Rs.25 + Rs.25) | Rs.5,000 per return |
| GSTR-3B nil return | Rs.20 (Rs.10 + Rs.10) | Rs.500 per return |
| GSTR-9 | Rs.200 (Rs.100 + Rs.100) | 0.5% of turnover in state |
Interest is separate. 18% per annum under Section 50, day-by-day on unpaid tax. A garment retailer in Aundh, Pune who files GSTR-3B for March 2026 twenty-five days late on Rs.84,600 owes roughly Rs.1,250 in late fees and Rs.1,043 in interest. One outlet. Multiply that across six GSTINs and annual leakage crosses Rs.50,000 before anyone notices.
Why Does GST Return Filing Matter for Indian SMEs?
ITC is working capital. That is the simplest way to put it. If a supplier of yours misses their GSTR-1 filing for even one month, the credit you were counting on to offset your output tax vanishes from your GSTR-2B. You pay cash instead.
We have seen this at Petpooja firsthand. One Invoice client in Vastrapur, Ahmedabad, lost Rs.3,00,000 in blocked ITC over a single quarter because two packaging suppliers went three months without filing. The invoices existed. But the portal treated the credit as if it did not.
And since 1 July 2025, any return more than three years overdue cannot be filed on the portal anymore. The window closes permanently. So does the ITC.
How Petpooja Invoice Helps with GST Return Filing
Petpooja Invoice applies the correct CGST, SGST, or IGST split at the point of billing itself, not after the fact in an Excel sheet. The Tally integration syncs invoice data into your books so GSTR-1 numbers match your ledger on filing day without manual reconciliation. Above Rs.5 crore turnover, e-invoices pre-fill GSTR-1 Table 4 on their own; clients like Swaroopa Reddy close GSTR-1 filing within a day of running the sync.
Frequently Asked Questions
GSTR-1 is invoice-level: every B2B invoice with buyer GSTINs, B2C sales totals, credit notes, export invoices. GSTR-3B is the payment summary where you declare output tax, claim ITC, and settle net liability. If these two do not reconcile, the portal flags it via ASMT-10. Check your numbers before filing 3B.
You lose the credit. Full stop. Section 16(2)(aa) of the CGST Act says the invoice must show up in your GSTR-2B before you can claim ITC. No filing from the supplier, no credit on your end. The only fix is chasing them to file, which, frankly, is harder than it sounds when the supplier is a small outfit with one accountant.
18% per annum under Section 50 on unpaid tax, calculated daily. If you claimed excess ITC and later reversed it, that portion attracts 24% under Section 50(3). Both charges sit on top of the per-day late fee.
Not always. Below Rs.2 crore turnover, you are exempt. Above that threshold, mandatory. Cross Rs.5 crore and GSTR-9C (the self-certified reconciliation statement) kicks in too, which is where CAs tend to spend most of December.
Quarterly Return Monthly Payment. Available if turnover is under Rs.5 crore. You file GSTR-1 and GSTR-3B once a quarter, but pay tax every month via PMT-06 by the 25th. To avoid freezing your buyers’ ITC during the two months you are not filing, upload B2B invoices through the Invoice Furnishing Facility (IFF). A lot of businesses forget that second part.
Added to the GST portal in October 2025. Before your GSTR-2B finalises each month, IMS shows you every invoice your suppliers reported. You can accept, reject, or put any invoice on hold. Do nothing and every invoice is treated as accepted by default, which means incorrect credits land in your books and become your problem to reverse.
