GST Compliance Calendar for FY 2026-27

A GST compliance calendar is less a list of dates than a description of a rhythm. Almost nothing in it is specific to FY 2026-27: GSTR-1 has been due on the 11th and GSTR-3B on the 20th for years, and those dates sit in the rules rather than being announced each April. What changes from year to year is the handful of once-a-year actions that have to be finished before the year starts, and the annual deadlines that fall inside it for the year just gone. This is the operating version of the calendar for 1 April 2026 to 31 March 2027 — the monthly rhythm, the quarterly rhythm, the annual one-offs, and what a finance team actually does in each window.

How to read a GST calendar

Every due date below is the standing statutory date. CBIC extends individual due dates by notification from time to time, usually when the portal is unavailable near a deadline or when a year-end filing window is crowded. Those extensions are period-specific and cannot be predicted a year ahead, so treat this page as the default rule and confirm the exact date for the period you are filing on gst.gov.in before you rely on it.

If what you want is a single-year reference table of every return type and its date, that is GST return due dates, and the catalogue of which return applies to which registration is in types of GST returns. This post assumes you know which returns you file and want to know when, in what order, and what to do in the gaps.

What to settle before 1 April 2026

Five decisions expire with the financial year. None of them take long; all of them are expensive to discover in May.

Renew the LUT. A Letter of Undertaking covers one financial year. File Form RFD-11 for FY 2026-27 before 1 April 2026, and certainly before your first zero-rated supply of the year. Without a live LUT, exports have to move on payment of IGST and be refunded later. The mechanics are in LUT filing for exporters.

Confirm or change the QRMP choice. The opt-in and opt-out window for a quarter runs from the first day of the second month of the preceding quarter to the last day of the first month of the quarter — so the choice for April to June 2026 can be changed until 30 April 2026. The option then carries forward until you change it. Whether it suits you depends on how quickly your buyers need invoices in their GSTR-2B: see the QRMP scheme explained.

Opt into or out of composition. Form CMP-02 has to be filed before the financial year begins, not during it. Opting out is likewise a start-of-year decision, and an incoming composition dealer has stock-related declarations to make shortly after. The turnover limits are in the composition scheme limit.

Start a fresh invoice series. Tax invoices need a unique consecutive series for each financial year. Reset the numbering on 1 April 2026 in every system that issues invoices, including the ones finance does not own, and make sure the series in your e-invoicing setup matches.

Re-baseline the vendor master. Covered in full below, and the one item on this list that is not a filing.

The monthly rhythm

For a regular monthly filer, the year is twelve copies of the same fortnight. Outward supplies go up by the 11th, the summary return and the payment go out by the 20th, and the returns filed by other kinds of registration cluster between the 10th and the 20th.

Two of these are load-bearing and the rest are conditional on your registration type. The filing detail for each sits in the GSTR-1 filing guide and the GSTR-3B filing guide. The e-invoice line is worth flagging separately: where the 30-day reporting window applies to you, it is a rolling deadline attached to each invoice rather than a monthly one, and an invoice that misses it cannot be reported at all.

The quarterly rhythm: QRMP and composition

QRMP does not remove two months of work — it replaces the detailed return in those months with a payment and an optional invoice upload. The quarters for FY 2026-27 are April to June, July to September, October to December, and January to March 2027.

The 22nd and 24th split is by state group, not by turnover or preference, and it follows the state of the registration rather than your head office. A group with registrations in several states will have different dates for different GSTINs in the same quarter, which is the single most common cause of a surprise QRMP late fee. Choosing between the fixed-sum and self-assessment methods for the monthly instalment is covered in PMT-06 challan payment.

Annual returns and once-a-year actions

Inside FY 2026-27 you file the annual returns for FY 2025-26 and settle the last of that year's credit. These are the dates that reward being entered in a calendar a month early, because each one needs reconciliation work before the form can be filled at all.

The annual return is a consolidation, not a fresh computation, so the quality of the December filing is decided by how clean the monthly filings were — see the GSTR-9 annual return guide and, for composition dealers, the GSTR-4 return. Which threshold puts you into GSTR-9C is set out in GST audit and turnover limits.

What a finance team does in week 1, 2 and 3

The dates are the easy part. The reason teams miss them is that the work that has to happen before a return can be filed is not itself on any calendar. A workable monthly shape looks like this.

Week 1 (1st to 10th) — close the books and reconcile. Lock the previous month in your accounting system, pull the sales register, and check it against what will go into GSTR-1: missing invoices, credit notes not yet passed, place-of-supply errors on interstate transactions, and any document series gaps. Download GSTR-2B as soon as it is generated and start matching purchases against it. Anything unmatched at this point is a conversation with a vendor, and conversations take days.

Week 2 (11th to 13th) — file outward supplies. GSTR-1 goes on the 11th for monthly filers; the IFF, if you use it, goes by the 13th. After this point your buyers can see the invoices, and corrections move to GSTR-1A rather than being edited in place. QRMP filers file GSTR-1 in this window only in the month after a quarter ends.

Week 3 (14th to 25th) — compute, pay, file. Finalise eligible credit from the matched GSTR-2B, compute the liability, check the cash and credit ledger balances, and file GSTR-3B by the 20th. Pay first and file second: a return that cannot be submitted because the cash ledger is short on the evening of the 20th is a late filing. QRMP filers pay PMT-06 by the 25th in months one and two, and file the quarterly GSTR-3B on the 22nd or 24th after quarter end.

What a missed deadline costs

Missing a date costs two separate things, and they behave differently. The late fee is a per-day charge that runs under each Act — so ₹25 a day under CGST and ₹25 a day under SGST for a return with transactions, and ₹10 plus ₹10 for a nil return — and it is capped, with the cap scaled to turnover. The cap is why a return filed a fortnight late is an annoyance and one filed nine months late is a budgeted expense rather than a catastrophe.

Interest is the part that does not stop. It runs on the tax actually paid late, from the day after the due date until the day the payment is made, and it is not capped by anything. A large liability paid a month late costs far more in interest than the late fee that accompanied it, which is why paying on time and filing a day late is a much smaller problem than filing on time and paying late. The rates, the higher rate for wrongly availed credit and the worked examples are in GST late fee and interest.

The annual return has its own, heavier per-day fee with a cap expressed as a percentage of turnover, so a GSTR-9 left until the following year is one of the more expensive ways to be late. Separately, the Section 16(4) cutoff is not a fee at all — credit not claimed by 30 November 2026 for FY 2025-26 invoices is simply gone, and there is no payment that restores it. That rule is explained in the ITC time limit under Section 16.

The item nobody diarises: vendor GSTINs

Every calendar above is about your own filings. The compliance item that actually causes year-end surprises is somebody else's. Input tax credit depends on your supplier being registered and having filed, and a registration can be cancelled or suspended at any point in the year without anyone telling you. A vendor master verified in April and never touched again is accurate for about a month.

The failure is quiet. Invoices keep arriving, they look identical to last month's, and your accounting system happily books the credit. The mismatch surfaces in GSTR-2B, or later in the GSTR-9 reconciliation, by which time the supplier has been paid and the credit has to be reversed with interest.

Two habits fix it. Re-verify the whole vendor master at the start of the financial year, alongside the LUT and the invoice series, so the year begins from a known-good baseline. Then re-check continuously — at minimum before releasing payment to a vendor you have not transacted with in a while, and ideally on a schedule for the whole list. Doing that by hand on the portal stops being feasible somewhere around fifty vendors; automated daily vendor GSTIN monitoring describes the scheduled version.

Our API exists for exactly this job: one call returns registration details and GSTR filing history together, so a nightly sweep of your vendor master tells you both who is no longer active and who has stopped filing. It is ₹0.50 per verification pay-as-you-go, ₹0.40 once a single credit purchase crosses 2,500 credits, and purchased credits do not expire. You get 20 free credits on email verification, expiring 30 days after issue, so a one-off April baseline of a small vendor list costs nothing — create an account, read the API docs, or check the numbers on pricing. For a handful of one-off checks there are five free lookups a day at GST number search with no signup at all.

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