GST Due Dates 2026-27 – Your Complete Filing and Compliance Calendar

A tax consultant once got a call from a client at 9 pm on the 20th, in a full panic because he’d completely forgotten GSTR-3B was due that day. Nothing out of the ordinary has occurred in the end: a small overdue charge, interest charges, and a lesson learned. Nevertheless, this story stands the test of time since it is rather common. Companies often miss these deadlines not out of negligence or lack of concern. They miss them because six or seven different dates are floating around in any given month, with no single place that pulls them all together.

So here’s that place, at least for FY 2026-27. Every major GST return, when it’s due, what happens if you’re late, and a few habits that’ll stop you from being the one calling your CA at 9 pm.

GST Due Dates Calendar 2026-27

Return	Frequency	Due Date
GSTR-1	Monthly	11th of the following month
GSTR-1 (QRMP)	Quarterly	13th of the month after the quarter
GSTR-3B	Monthly	20th of the following month
GSTR-7 (TDS)	Monthly	10th of the following month
GSTR-8 (TCS)	Monthly	10th of the following month
GSTR-6 (ISD)	Monthly	13th of the following month
GSTR-5 / 5A	Monthly	13th of the following month
GSTR-4 (Composition)	Annual	30 April 2027
GSTR-9 (Annual Return)	Annual	31 December 2027
GSTR-9C (Reconciliation)	Annual	31 December 2027

Imp Note: A technical glitch, a festival, sometimes just a notification nobody expects, and a due date shifts by a day or two. Last year, it happened with a March filing after portal issues pushed things by 24 hours. So treat this as your working map, but glance at the official GST portal before you actually hit submit, especially near month-end.

GSTR-1 

GSTR-1 is where outward supplies get reported. Sales, in plain English. Monthly filers owe it by the 11th of the next month; if you’re on QRMP (open to anyone under ₹5 crore turnover), you get to file quarterly instead, by the 13th after the quarter closes.

Here’s the part people underestimate: this return isn’t really “yours” in isolation. Whatever you put in GSTR-1 becomes someone else’s Input Tax Credit. Delay your filing, and you’ve quietly delayed a buyer’s ITC, too, which, in my experience, is exactly the kind of thing that makes a client start asking pointed questions about your billing process.

If GSTR-1 is just one of several forms you’re juggling each month, there’s a decent explainer on how businesses track multiple types of GST returns that’s worth a look. The real problem is usually visibility, not the filing itself.

GSTR-3B 

If GSTR-1 is the reporting return, GSTR-3B is the one where money actually leaves your account. It’s the monthly summary, outward supplies, inward supplies, tax liability, all of it, and it’s due on the 20th.

This is also, unsurprisingly, the return most people associate with a bad week. Because it’s not just paperwork, it’s a payment, and the two arriving on the same date tends to catch businesses with tight working capital off guard. I’ve seen retailers plan their entire cash cycle around the 20th almost by instinct, the way you’d plan around rent day.

The fix isn’t complicated, it’s just reminders, set early enough that the 20th stops being a surprise. There’s a decent rundown on GST payment due date alerts if you’re tired of relying on your own memory for this.

The forms nobody remembers exist

GSTR-1 and GSTR-3B get all the attention because nearly every registered business files them. But there’s a second tier of returns that only apply to specific situations, and precisely because they’re niche, they’re the ones that slip through the cracks.

GSTR-7 covers anyone deducting TDS under GST, due on the 10th. GSTR-8 is its cousin for e-commerce operators collecting TCS, also the 10th. GSTR-6 related to Input Service Distributors is due on the 13th. GSTR-5/5A pertains to the non-resident taxable persons and OIDAR providers and is due on the 13th as well. 

None of these is complicated in itself. The issue is purely psychological; they don’t live in the same mental slot as “the usual monthly filing,” so they get forgotten until a notice shows up asking why they weren’t filed. If any of these apply to your business, it genuinely helps to give them their own separate reminder instead of assuming they’ll get swept up with everything else.

Then there’s the annual paperwork

The taxpayers who fall under the purview of the composition scheme are required to file their annual return under GSTR-4 by 30 April 2027 for FY 2026-27. Taxpayers who surpass the composition limit must file two more complex documents – GSTR-9 and GSTR-9C, which are both required by 31 December 2027. What makes these two painful isn’t the filing itself; it’s that they force everything from the whole year to line up. Twelve months of GSTR-1 and GSTR-3B numbers get consolidated here, and any small inconsistency that’s been quietly sitting in your books suddenly becomes very visible.

The honest advice is to reconcile monthly, not annually. Waiting until December to check whether a year’s worth of returns actually match is asking for a bad surprise. For anyone curious how this consolidation logic evolved, this piece on GSTR-3 filing is a decent read. GSTR-3 itself isn’t in active use anymore, but the underlying idea of tying everything back to one consolidated return is basically what GSTR-9 does today.

And if you do miss one

Late fees aren’t a flat slap on the wrist; they accrue per day, separately under CGST and SGST, which means a “small” delay adds up faster than it looks like it should on day one. Interest kicks in too, on whatever tax was actually due, and if the pattern repeats often enough, it starts drawing the department’s attention in the form of notices.

There’s also a rule worth knowing about that a lot of businesses still aren’t fully aware of: GST returns can’t be filed at all beyond three years from their original due date anymore. That’s not a typo. Past that window, the return isn’t late, it’s simply unfilable. Old, neglected returns used to be a “get to it eventually” problem. They’re not anymore.

None of this means a notice is the end of the world. Most get sorted out with the right paperwork and a prompt reply; I’ve seen plenty resolved without any real damage. But it’s time you’d rather not spend, and it’s avoidable. If you want to understand what actually triggers these notices before one lands in your inbox, this rundown on GST notices covers the common ones.

GSTR-2B doesn’t have a due date, but treat it like one anyway

Technically, GSTR-2B isn’t something you “file”; it’s auto-generated, usually landing around the 14th of the month. No deadline pressure, no penalty for it being late, which is exactly why people ignore it. That’s a mistake. It’s your reference point for reconciling Input Tax Credit before GSTR-3B goes in, and skipping that step is how businesses end up claiming ITC that doesn’t survive an audit.

This piece on recent GSTR-2B changes is worth a read if you haven’t looked at it since the rules shifted.

Making the calendar actually stick

Nobody misses these deadlines because they don’t care. They miss them because the calendar has too many moving pieces, different frequencies, different forms, some monthly, some annual, some that only apply if your business happens to fit a specific description.

A few things genuinely help here, not as a checklist to admire but as habits worth building:

Set a separate reminder for each form instead of one vague “GST day” on your calendar. Reconcile GSTR-2B against your purchases every month, not once a year when GSTR-9C forces the issue. Keep some kind of running log, even a basic spreadsheet, of what’s filed and what isn’t, because busy months are exactly when things get missed. Whenever possible, use programs that automatically extract return details straight from your invoices, as opposed to making you recreate every single form every month.

This is where MargBooks software shines because it handles everything from invoicing to filing and reconciling instead of having to manage things in three repositories.

Conclusion

There are no major changes in FY 2026-27 in terms of practice; GSTR-1 filings take place every month, and GSTR-3B returns are disclosed every month while crucial yearly filings happen once a year. The main difference is that businesses assign different levels of importance to these activities on a monthly basis, even if it is not ignored entirely.

You need to save the table, set up reminders to use it consistently, and make sure that you reconcile your statements regularly instead of panicking in December. It is not too demanding and helps in avoiding a huge amount of expenses and frustrations in the future. 

FAQs

1. What happens if I miss the GSTR-3B due date by just a day or two?

You’ll still owe a late fee, it’s charged per day, so a two-day delay isn’t the end of the world, but it’s not free either. Interest also kicks in on whatever tax was actually due. It won’t ruin your month, but there’s genuinely no upside to waiting, so it’s worth just paying it as soon as you realize.

2. I’m on the QRMP scheme. Does that mean I only have to worry about GST once every three months?

Not quite, and this trips people up more than you’d think. QRMP lets you file GSTR-1 quarterly, but GSTR-3B and your tax payment are usually still monthly (unless you’ve opted for the fixed-sum method). So you’re getting relief on one form, not a free pass on the whole cycle.

3. Can I still file an old GST return I forgot about from a couple of years ago?

Depends how old. There’s now a hard three-year cutoff from the original due date; past that, the portal simply won’t let you file it anymore. It’s not a “figure it out eventually” situation like it used to be, so if something is sitting unfiled, it’s worth checking the timeline sooner rather than later.

4. Why does my GSTR-2B matter if there’s no actual deadline attached to it?

Because it’s quietly doing a lot of work behind the scenes. It’s what you reconcile your Input Tax Credit against before filing GSTR-3B, and it now feeds directly into your annual return too. No deadline just means no one’s forcing you to look at it, which is exactly why it’s easy to ignore until something doesn’t add up.

5. What are the differences between GSTR-9 and GSTR-9C, and am I required to file both? 

GSTR-9 is the yearly return that summarizes everything you submitted that year, while GSTR-9C is the reconciling report and should only be submitted once you exceed the specified turnover limit.