GST Return Filing in India: Every Form, Every Deadline, Explained Simply

Getting a GSTIN is a one-time job. Filing returns is forever.

Every registered business has to tell the government what it sold, what it bought, and how much tax it owes. This should be done every month or every quarter, then once more at year-end. Miss a deadline, and the late fee starts running the next day. Miss enough of them, and you lose your e-way bills, then your registration.

Filing also changed more between 2025 and 2026 than in the previous five years put together. GSTR-3B no longer lets you edit your own tax figures. Your input tax credit now depends on a dashboard you have to check every month. And returns older than three years are simply blocked.

Here is what to file, when to file it, and what to watch out for.

What Is GST Return Filing?

A GST return is a statement you submit on the government portal listing your sales, your purchases, the tax you collected, and the tax you paid. The department uses it to work out what you owe.

There isn't one GST return. There are about a dozen forms, and which ones apply to you depends on your registration type and your turnover. Most businesses deal with just two of them each period, plus one at year-end.

The two that matter most:

• GSTR-1 - It reports what you sold, invoice by invoice, for B2B sales
• GSTR-3B - It is the summary where you actually pay the tax

You need an active GSTIN before any of this starts. If you have not registered yet, start with GST registration: the filing clock begins the moment your certificate is issued, whether or not you make a single sale.

Who Files, and How Often?

Monthly Filers

If your annual turnover is above ₹5 crore, you file GSTR-1 and GSTR-3B every month. No choice.

QRMP Filers

If your turnover is up to ₹5 crore, you can join the Quarterly Return Monthly Payment scheme. You file both returns once a quarter, but you still pay tax every month.

That last part catches people out. QRMP reduces your paperwork, not your payment schedule. You pay monthly through challan PMT-06 by the 25th, using either a fixed sum (35% of the previous quarter's cash payment) or your own calculation.

QRMP also gives you the Invoice Furnishing Facility (IFF). It is optional. If your B2B customers want their credit in months one and two rather than waiting for the quarter to close, you upload those invoices by the 13th. If nobody is complaining, skip it.

You can switch in and out of QRMP each quarter on the portal.

Composition Dealers

Under the composition scheme, you file a quarterly payment challan, CMP-08, and one annual return, GSTR-4. No GSTR-1, no GSTR-3B. This is a much easier process, but you cannot claim input tax credit.

Everyone Else

Non-resident taxpayers, input service distributors, TDS deductors, e-commerce operators, and UIN holders each have their own form. The table below covers all of them.

Types of GST Returns: The Complete List

Note what is not on this list. GSTR-2 and GSTR-3 were suspended years ago and never came back. Any guide still telling you to "validate GSTR-2A and file GSTR-2" is describing a system that no longer exists.

GST Return Due Dates

Why QRMP Has Two Different Dates

Quarterly GSTR-3B deadlines are staggered by state to spread the load on the portal.

• 22nd: Gujarat, Maharashtra, Karnataka, Tamil Nadu, Kerala, Telangana, Andhra Pradesh, Goa, Madhya Pradesh, Chhattisgarh, and the southern and western union territories
• 24th: Uttar Pradesh, Delhi, Haryana, Punjab, Rajasthan, Bihar, West Bengal, Odisha, Jharkhand, Assam, the north-eastern states, Himachal Pradesh, Uttarakhand, Jammu & Kashmir, Ladakh and Chandigarh

Check yours once and note it down. Assuming the 22nd when you are on the 24th list is harmless. Assuming the 24th when you are on the 22nd list costs you two days of late fee.

Three Rules That Changed How Filing Works

This is the part most guides have not updated.

1. GSTR-3B Is Hard-Locked

From the July 2025 tax period onwards, the tax liability in GSTR-3B is auto-filled from your GSTR-1, IFF, and GSTR-1A, and you cannot edit it. A second advisory in July 2025 locked Table 3.2 as well, which covers inter-state supplies to unregistered buyers and composition dealers.

What this means in practice: GSTR-1 is now the return that decides your tax. GSTR-3B just collects the payment.

Before, a wrong figure in GSTR-1 could be quietly corrected while filing GSTR-3B. That door is shut. If you spot a mistake after filing GSTR-1, your only route is GSTR-1A. It’s an amendment form for the same tax period, available after the GSTR-1 due date and up until you file GSTR-3B. Fix it there, and the corrected number flows through automatically.

So the habit to build is simple: check GSTR-1 carefully before filing it, not after.

2. IMS Is Now Compulsory

The Invoice Management System is a screen on the portal where every invoice, credit note, and debit note your suppliers file lands, waiting for you to act on it. You can accept, reject, or mark it pending. Only accepted records flow into your GSTR-2B as claimable credit.

It went live in October 2024 as an optional tool. From 1 April 2026, it is mandatory for regular filers under the rewritten Section 38 of the CGST Act.

Here is the trap. Doing nothing is not neutral. Any invoice you leave untouched is treated as accepted when GSTR-2B is generated on the 14th. So if a supplier uploads a wrong invoice, or an inflated one, and you never look at your dashboard, that credit lands in your return as if you had approved it. When it is later reversed, the interest and penalty are yours, not theirs.

Fifteen minutes on the IMS dashboard each month is now part of the job. If you are not sure which credits you are entitled to in the first place, read our guide to input tax credit.

3. Returns Older Than Three Years Are Blocked

Under the Finance Act 2023, you cannot file a return more than three years after its due date. The portal started enforcing this from July 2025, with hard blocks from October 2025. It applies to GSTR-1, GSTR-3B, GSTR-4, GSTR-5, GSTR-6, GSTR-7, GSTR-8, GSTR-9 and GSTR-9C.

Once the window shuts, it does not reopen. No appeal, no request, no waiver.

And here is the sting: the tax does not go away. You simply lose the ability to file, while the department keeps the right to demand the tax, interest, and penalty. You end up with a permanent hole in your compliance record and no way to patch it.

If you have old returns sitting unfiled, count the months today.

Your Filing Month, Day by Day

For a regular monthly filer, the rhythm looks like this.

By the 10th: Chase suppliers who have not uploaded your invoices yet. Once GSTR-2B is cut on the 14th, a missing invoice is next month's problem.

11th: File GSTR-1. Your sales are now locked for the period.

11th to 14th: Go through the IMS dashboard. Accept what is genuine, reject what is not, and mark anything disputed as pending.

14th: GSTR-2B is generated. This is your credit for the month. Compare it against your purchase register.

14th to 19th: If you spotted a GSTR-1 error, fix it in GSTR-1A now.

20th: File GSTR-3B and pay. The liability is pre-filled and locked; you are confirming ITC and settling the balance in cash.

QRMP filers run the same loop, with GSTR-1 on the 13th after the quarter, the PMT-06 challan by the 25th each month, and GSTR-3B on the 22nd or 24th.

The invoices feeding all of this have to be correct at source. Getting the format right is covered in GST invoicing. And if your turnover is above ₹5 crore, your invoices must carry an IRN: see GST e-invoicing, which also auto-populates much of your GSTR-1 for you.

How to File GSTR-1 and GSTR-3B

Filing GSTR-1

1. Log in to gst.gov.in and go to Services → Returns → Returns Dashboard
2. Pick the financial year and period, then select ‘Prepare Online’ under GSTR-1
3. Enter B2B invoices individually with the buyer's GSTIN, invoice number, date, value, tax rate, and place of supply
4. Enter B2C sales as consolidated totals, split by rate and by state where required
5. Add exports, credit and debit notes, advances and HSN summary in their tables
6. Check the summary, then file with DSC or EVC

Exporters report zero-rated supplies in Table 6A. If you ship without paying IGST, you need a Letter of Undertaking on file first: see GST LUT forms.

Filing GSTR-3B

1. Open GSTR-3B for the same period from the Returns Dashboard
2. Table 3 is already filled from your GSTR-1 and locked — read it; don't try to change it
3. Confirm your ITC figures in Table 4 against GSTR-2B, reversing anything ineligible
4. Declare exempt and non-GST inward supplies where they apply
5. Offset the liability against available credit, then pay any balance in cash through PMT-06
6. File with DSC or EVC and save the acknowledgement

A return with unpaid tax cannot be filed. The payment and the filing happen together.

Late Fees, Interest and What Else Goes Wrong

The Money

Two things worth knowing. Late fees and interest can only be paid in cash. You cannot use input tax credit for either. While the late fee is capped, interest is not. On a large unpaid liability, interest is the part that actually hurts.

A nil return still attracts a fee. ₹20 a day sounds like nothing, but people with no sales are exactly the people who forget, and it runs quietly across both returns for months.

The Knock-On Effects

The money is the smallest part. Miss enough filings and the system starts closing doors.

• You cannot skip ahead

Returns must be filed in order. One unfiled GSTR-3B blocks every later one.

• E-way bills stop

Miss two consecutive GSTR-3B filings (or two quarters under QRMP) and the portal blocks e-way bill generation. Your goods stop moving.

• Your buyers lose credit

If your GSTR-1 is not filed, your invoices never reach your customers' GSTR-2B. Expect the calls.

• Your registration can be cancelled

Six months of non-filing for a regular taxpayer, or three consecutive tax periods for a composition dealer, and the officer can cancel under Section 29. Getting it back means filing everything anyway, plus fees. If cancellation is where you are headed deliberately, do it properly through GST registration cancellation.

Can You Revise a GST Return?

No. There is no revised return under GST, and this surprises people coming from income tax.

What you have instead:

• Same period, GSTR-1 only: Use GSTR-1A before you file GSTR-3B
• Any later error: Correct it in a subsequent period's return, with interest if the tax was short-paid
• Whole year: Reconcile in GSTR-9

The outer limit for fixing a year's mistakes is 30 November of the following financial year, or the date you file the annual return, whichever is earlier. That same date is the deadline for claiming any missed input tax credit. After it, the credit is gone for good. The year-end reconciliation itself is covered in GST annual return filing.

Common Filing Mistakes

From what we see across client files, these are the repeat offenders.

• Treating GSTR-3B as the return that matters

Since hard-locking, GSTR-1 is where your liability is decided. Errors caught at the 3B stage are too late.

• Ignoring IMS

Deemed acceptance quietly pulls wrong credit into your return.

• Claiming ITC that isn't in GSTR-2B

If your supplier hasn't filed, the credit isn't yours yet, however valid your invoice looks.

• Wrong place of supply

Charging CGST and SGST on an inter-state sale means paying IGST again and claiming a refund of the first payment.

• Forgetting reverse charge

Goods transport, legal fees, director's remuneration, and imports of services all attract RCM, and it is easy to miss on the purchase side.

• Skipping nil returns

No sales does not mean no filing.

• Letting the accountant hold the calendar

When the person handling your filings changes jobs, the deadlines should not leave with them.

What do we do differently?

We reconcile GSTR-2B against your purchase register before GSTR-3B is filed, not after a notice arrives. We review GSTR-1 with you before submission because that is now the only practical correction window.

Never Miss Another Deadline

We handle the full monthly cycle, from GSTR-1, IMS review, and GSTR-2B reconciliation to GSTR-3B, and tell you what you owe before the due date, not after it. If you have pending returns from earlier years, send them over. Some may be close to the three-year cut-off, and that is worth checking now rather than later.

Book a free consultation: Share your GSTIN and turnover, and we will map out exactly which returns apply to you.

Good filing depends on good records. If your invoicing is still running on spreadsheets, GST billing software will save you more time than any amount of careful filing will.