GST Filing Due Dates: Monthly & Quarterly Compliance Calendar

Most GST penalties we see come not from complex tax questions but from a missed date: a GSTR-1 filed on the 12th instead of the 11th, a QRMP payment forgotten in the second month, or an annual return left until the last week of December. If you run a startup or small business, knowing your GST filing due dates is the cheapest compliance win available.

In short: monthly filers file GSTR-1 by the 11th and GSTR-3B by the 20th of the following month. QRMP taxpayers (turnover up to ₹5 crore) file GSTR-1 by the 13th and GSTR-3B by the 22nd or 24th of the month after each quarter, paying tax monthly through PMT-06 by the 25th. The annual return GSTR-9 (and GSTR-9C where applicable) for FY 2025-26 is due by 31 December 2026.

Key Takeaways

• GSTR-1 is due on the 11th (monthly) or the 13th after the quarter (QRMP); GSTR-3B is due on the 20th (monthly) or 22nd/24th after the quarter (QRMP).
• QRMP filers must still deposit tax for months 1 and 2 of each quarter through PMT-06 by the 25th.
• GSTR-2B is generated on the 14th; actions in the Invoice Management System (IMS) should be completed before you file GSTR-3B.
• GSTR-9/9C for FY 2025-26 is due on 31 December 2026.
• Returns cannot be filed after three years from their original due date, so old pending returns must be cleared now.
• CBIC can extend any due date by notification, so always confirm on gst.gov.in before relying on a date.

What GST Due Dates Cover and Who They Apply To

Every GST-registered person, whether a company, LLP, firm or proprietor, has a filing calendar from the date of registration, even in months with no business. A nil return is still a return, and missing it attracts a late fee.

Your calendar depends on three choices: whether you are a regular taxpayer or under the composition scheme, whether you file monthly or quarterly under the QRMP scheme, and whether you have special roles such as TDS deductor, e-commerce operator or Input Service Distributor. If you have only recently obtained your GST registration number, the first return is due for the month in which registration became effective.

GST Return Due Date Master Table

The table below summarises the main returns under the CGST Act and Rules as they stand on 22 September 2026.

Monthly Filing vs the QRMP Scheme

The Quarterly Return Monthly Payment (QRMP) scheme is open to taxpayers with aggregate turnover up to ₹5 crore in the preceding financial year. You file quarterly but still pay tax monthly, so it reduces paperwork, not the number of dates.

If your customers are mostly GST-registered businesses, they want your invoices in their GSTR-2B every month. Choosing QRMP without filing IFF delays their credit.

Monthly Filer Calendar: October–December 2026

For a monthly filer, the October, November and December 2026 tax periods look like this:

QRMP Calendar: Worked Example for the October–December 2026 Quarter

Here is the complete month-by-month schedule for a QRMP taxpayer for the third quarter of FY 2026-27.

For PMT-06, you can either pay 35% of the cash liability of the previous quarter (fixed sum method) or compute actual liability for the month (self-assessment method). Under the fixed sum method, if your cash tax for July–September 2026 was ₹3,00,000, you would deposit ₹1,05,000 each in November and December and settle the balance in the quarterly GSTR-3B.

22nd or 24th: Which Date Applies to You?

The date depends on the state of your principal place of business. Broadly, western and southern states (such as Maharashtra, Gujarat, Karnataka and Tamil Nadu) file by the 22nd, while northern and eastern states and UTs, including Delhi, Uttar Pradesh and West Bengal, file by the 24th. Check the notified list on gst.gov.in.

Annual Returns: GSTR-9 and GSTR-9C for FY 2025-26

GSTR-9 consolidates the year's outward supplies, ITC and tax paid. For FY 2025-26, it is due on 31 December 2026. It is mandatory if your aggregate turnover exceeded ₹2 crore, and optional below that.

GSTR-9C is a self-certified reconciliation between your audited financial statements and GSTR-9, required where turnover exceeded ₹5 crore. It is due on the same date. Because it depends on final books, your financial statement preparation and audit need to be completed well before December.

Composition taxpayers file GSTR-4 instead, and the FY 2025-26 GSTR-4 was due on 30 April 2026. If it is still pending, file it immediately to stop the late fee growing.

One related deadline is often missed: unclaimed ITC for FY 2025-26 can be taken only up to 30 November 2026 under Section 16(4), and corrections for that year should be made in returns by then. Starting the annual reconciliation in October leaves room for both.

The Monthly GST Workflow That Makes Due Dates Easy

Due dates become stressful only when work starts on the due date. This is the monthly rhythm our team runs for monthly filers.

1. 1st to 10th: close sales for the previous month, record all invoices, credit notes and debit notes in the books, and match e-invoice (IRN) data where applicable.
2. By the 11th: file GSTR-1 (or IFF by the 13th for QRMP filers). Review the auto-drafted summary before submitting.
3. Throughout the month: open the Invoice Management System (IMS) and accept, reject or keep pending each supplier invoice. Invoices you do not act on are deemed accepted when GSTR-2B is generated.
4. 14th: GSTR-2B for the month is generated. Download it and reconcile it with your purchase register.
5. 15th to 18th: follow up with suppliers whose invoices are missing, and decide on reversals under Section 17(5) or Rule 37.
6. By the 19th: compute net tax liability, arrange funds and create the challan (PMT-06 format).
7. By the 20th: file GSTR-3B and make payment.

Keeping your monthly bookkeeping records closed by the 5th or 6th is what makes this cycle work.

Late Fee and Interest If You Miss a Date

Late fee is charged per day of delay, and interest runs on unpaid tax from the day after the due date. Both are payable in cash.

Worked Example

A Delhi-based services company with turnover of ₹1.2 crore files its October 2026 GSTR-3B on 5 December 2026 instead of 20 November, a delay of 15 days, with cash tax of ₹1,50,000.

• Late fee: ₹50 × 15 = ₹750 (within the ₹2,000 cap).
• Interest: ₹1,50,000 × 18% × 15/365 = about ₹1,110.
• Total cost of the delay: roughly ₹1,860, plus the risk that customers' ITC is disrupted.

The 3-Year Time Bar on Old Returns

From 2025, the GST portal enforces the rule that GSTR-1, GSTR-3B, GSTR-9 and related returns cannot be filed after three years from their original due date. Once that window closes, the return is permanently barred.

This hits businesses that registered, went dormant and never filed. A barred return can complicate cancellation and clean-up of the registration, while the department can still raise a demand. Treat any returns pending from 2023-24 or earlier as urgent.

What Changed in 2025–26

• IMS is now part of the monthly cycle; unactioned invoices are deemed accepted when GSTR-2B is generated.
• GSTR-3B Table 3 is hard-locked from the July 2025 tax period. Outward liability auto-filled from GSTR-1, IFF or GSTR-1A cannot be edited in 3B; corrections must go through GSTR-1A before filing GSTR-3B.
• Hard-locking of ITC in Table 4 is being phased in. Follow the latest GSTN advisory on gst.gov.in for your applicable tax period.
• GST 2.0 rate rationalisation from 22 September 2025 moved most items to 5% and 18%, with 40% for sin and luxury goods.

How to Never Miss a GST Due Date: A Simple System

A reliable system does not depend on one person remembering. It needs a written calendar, internal cut-offs earlier than legal due dates, and a named owner.

1. Set internal deadlines two days before each legal one. Treat the 9th as your GSTR-1 date and the 18th as your GSTR-3B date.
2. Put every date in a shared calendar with reminders three days and one day before, including PMT-06, CMP-08 and GSTR-9.
3. Keep funds ready. Transfer the estimated GST amount into the electronic cash ledger by the 18th so bank holidays do not delay payment.
4. Keep DSC or EVC access in order. A company whose authorised signatory is travelling or has an expired DSC cannot file on time.
5. Review CBIC notifications and GSTN advisories monthly. Due dates can be extended, and new validations appear without much notice.

If you sell on marketplaces, add a step to reconcile the TCS credit reported by the operator in GSTR-8; our e-commerce accounting team does this for sellers every month. Also align GST dates with your income tax calendar, since the advance tax instalment of 15 December 2026 falls in the same fortnight as the November GSTR-3B.

How Startup India Files Helps You Stay on the GST Calendar

• A personalised compliance calendar based on your registration type, state and QRMP choice.
• End-to-end GST return filing: GSTR-1, IFF, GSTR-3B, PMT-06, CMP-08 and GSTR-4.
• Monthly GSTR-2B and IMS reconciliation with a list of supplier follow-ups.
• Preparation of GSTR-9 and GSTR-9C for FY 2025-26 ahead of 31 December 2026.
• Clean-up of old pending returns before they hit the three-year time bar.

Our team in Ramesh Nagar, Delhi, works with startups and SMEs across India, and our wider tax and compliance services mean GST, TDS and income tax dates sit in one plan. Call +91-9971668562 or reach us through our contact page to get your calendar set up this month.

Frequently Asked Questions

What is the due date for GSTR-1 for October 2026?

A monthly filer must file October 2026 GSTR-1 by 11 November 2026. A QRMP filer can upload October B2B invoices in IFF by 13 November 2026 and file the quarterly GSTR-1 by 13 January 2027.

Is PMT-06 payment compulsory under QRMP?

Yes, tax for the first two months of each quarter must be deposited by the 25th of the following month, unless there is no liability after considering available ITC. Late deposit attracts 18% interest.

When is GSTR-9 for FY 2025-26 due?

GSTR-9 and GSTR-9C for FY 2025-26 are due by 31 December 2026, unless CBIC extends the date by notification. GSTR-9 is optional for turnover up to ₹2 crore.

Do I need to file GST returns if there were no sales?

Yes, a nil return must be filed for every period while registration is active. A nil return filed late attracts ₹20 per day, up to ₹500 per return.

Can I still file a GST return from 2022?

Only if three years have not passed since its original due date. Returns older than that are time-barred on the portal and cannot be filed.

Can Startup India Files handle both monthly and QRMP filings?

Yes, we handle monthly filers, QRMP taxpayers and composition dealers, and we also advise on whether switching between monthly and QRMP makes sense for your customer mix.

Final Word

GST due dates are fixed, predictable and unforgiving. Build your month around the 11th, 14th and 20th (or the QRMP equivalents), keep books closed early, and review CBIC notifications for extensions. Do that consistently and late fees, interest and time-barred returns simply stop being a problem.

This guide is for general information based on the law as on 22 September 2026. Rules and portal processes change — confirm on the official portal or speak to our team before filing.