GST due dates calendar FY 2026-27

The core monthly GST due dates are GSTR-1 by the 11th and GSTR-3B by the 20th of the following month, while QRMP taxpayers file GSTR-1 quarterly (13th) and GSTR-3B by the 22nd or 24th. The annual return GSTR-9/9C is due by 31 December following the financial year.

Monthly and quarterly returns

Other periodic returns

Annual return

GSTR-9 / GSTR-9C for a financial year is due by 31 December of the following year (for example, FY 2025-26 by 31 December 2026). GSTR-4 (annual, composition) is due by 30 June following the year.

Practical notes

• Dates falling on a holiday are not automatically extended — file ahead.
• Sequential filing rules block a later GSTR-1/3B if an earlier one is pending.
• Track all this in the NumberIQ due-date calendar.
• Verify any CBIC extensions notified for specific periods.

The monthly compliance rhythm

Two structural rules shape the calendar. First, GSTR-1 is locked to GSTR-3B — you cannot file 3B without the period's GSTR-1, and sequential filing is mandatory. Second, the three-year bar: from the October 2025 tax period onwards, returns cannot be filed more than three years after their due date, converting old non-filings from a late-fee problem into a permanent one.

Annual and event-driven deadlines

• GSTR-9 / 9C (annual return and reconciliation): 31 December following the financial year — 31 December 2027 for FY 2026-27. GSTR-9 is optional below Rs.2 crore turnover; 9C applies above Rs.5 crore.
• ITC time limit: Section 16(4) — ITC for FY 2026-27 invoices must be claimed by the earlier of 30 November 2027 (in the return for October 2027) or the annual return date.
• Credit notes: same 30 November outer limit for reducing output liability.
• LUT renewal for zero-rated exporters: file the fresh Letter of Undertaking before the first export of each financial year — set the reminder for late March.
• Composition: CMP-08 quarterly by the 18th; annual GSTR-4 by 30 June following the year.

Building a close calendar that actually prevents interest

The dates above are filing deadlines; the cash cost sits in payment timing. Interest under Section 50 runs from the 3B due date on the net cash liability, so the working-capital decision is simply: file and pay by the 20th. Our recommended sequence for a monthly close: freeze sales register by the 5th, file GSTR-1 by the 9th (buffer before the 11th), download GSTR-2B on the 14th (it generates on the 14th), complete the 2B-to-purchase-register reconciliation by the 17th, and file 3B with payment on the 19th. That two-day buffer absorbs portal slowdowns, which cluster on statutory due dates. Track CBIC due-date extensions at gst.gov.in — extensions are notification-specific and never assume one.

QRMP: the choices inside the scheme

Taxpayers up to Rs.5 crore turnover can file quarterly with monthly payment. For months 1 and 2 of each quarter, pay by the 25th through PMT-06 using either the fixed-sum method (35% of the previous quarter's cash tax, no interest exposure if paid on time) or the self-assessment method (actual liability net of ITC, requires a real 2B pull each month). The fixed-sum route is safer for stable businesses; self-assessment suits seasonal ones where 35% would over-remit. Invoices can be pushed to buyers monthly via the IFF (by the 13th, capped at Rs.50 lakh per month) so customers' ITC is not delayed by your quarterly cycle — a commercial courtesy that large customers increasingly demand contractually.

Late fees at a glance

Late fees are per Act (CGST and SGST separately), auto-computed at filing, and cannot be waived except by notification — build the calendar so they never arise. Cross-check current fee notifications at cbic.gov.in.