GST Compliance Calendar FY 2026-27: All Due Dates at a Glance

Every GST-registered business in India must meet 11 to 37 return filing deadlines per financial year, depending on the taxpayer category. Miss even one, and you face automatic late fees starting at ₹50 per day plus 18% annual interest on unpaid tax. The GST compliance calendar for FY 2026-27 (April 1, 2026 to March 31, 2027) follows the same structural framework as previous years, but staying organized across monthly GSTR-1, GSTR-3B, GSTR-7, GSTR-8, quarterly CMP-08, and annual GSTR-9 filings requires a clear, month-by-month plan. This guide maps every deadline for every taxpayer category - regular filers, QRMP scheme participants, composition dealers, ISDs, TDS deductors, and e-commerce operators - so you never pay an avoidable penalty. Bookmark this page or set up the reminders outlined below to keep your GST return filing on track throughout the year.

Complete Month-by-Month GST Compliance Calendar for FY 2026-27

The table below covers every major GST return deadline from April 2026 through March 2027. Use it as your master reference. Each row specifies the tax period (the month the transaction relates to), the return type, and the exact due date. Where QRMP scheme deadlines differ from regular monthly filing, both are noted.

Understanding GST Return Types and Filing Frequency

Before diving into scheme-specific details, here is a consolidated reference of every GST return type, its purpose, who must file it, and the standard due date cycle. Understanding this framework helps you identify exactly which returns apply to your business.

Most small and medium businesses only need to worry about GSTR-1, GSTR-3B, and GSTR-9. If your turnover is under ₹5 crore, you can use the QRMP scheme and reduce your filing count from 24 returns to 8 returns per year (plus monthly PMT-06 payments). That alone saves significant time and reduces the risk of missed deadlines.

QRMP Scheme: Quarterly Filing for Small Taxpayers

The Quarterly Return Monthly Payment (QRMP) scheme is one of the most useful GST simplifications available to small businesses. Introduced to reduce the compliance burden on taxpayers with lower turnover, it allows eligible businesses to file GSTR-1 and GSTR-3B on a quarterly basis instead of monthly - while still paying tax every month.

Eligibility and Opt-In Process

Any taxpayer with aggregate turnover up to ₹5 crore in the preceding financial year can opt for the QRMP scheme. The option is exercised on the GST portal under Services → Returns → Opt-in for Quarterly Return. You must select this option by the last day of the first month of the quarter. For FY 2026-27, the opt-in windows are:

• Q1 (April-June 2026): Opt in by April 30, 2026
• Q2 (July-September 2026): Opt in by July 31, 2026
• Q3 (October-December 2026): Opt in by October 31, 2026
• Q4 (January-March 2027): Opt in by January 31, 2027

How Monthly Payment Works Under QRMP

Even though returns are filed quarterly, tax must be paid monthly for the first two months of each quarter using the PMT-06 challan. The due date for PMT-06 is the 25th of the following month. Taxpayers can choose between two payment methods:

• Fixed Sum Method: Pay 35% of the tax paid in the previous quarter's GSTR-3B. This is the simpler option - the GST portal auto-populates the amount.
• Self-Assessment Method: Calculate your actual tax liability for the month based on your sales and ITC, and pay accordingly. This is more accurate but requires monthly bookkeeping.

The third month's tax is paid when you file your quarterly GSTR-3B. For example, for Q1 FY 2026-27: pay April's tax by May 25 via PMT-06, pay May's tax by June 25 via PMT-06, and file GSTR-3B for the entire quarter (with June's tax) by July 22 or 24 depending on your state category.

Invoice Furnishing Facility (IFF)

QRMP taxpayers can optionally upload B2B invoices for the first two months of each quarter using the IFF by the 13th of the following month. This allows your buyers to claim Input Tax Credit without waiting for your quarterly GSTR-1. If you do not use IFF, your buyers can only claim ITC after your quarterly GSTR-1 is filed. For businesses with significant B2B transactions, using IFF is strongly recommended to maintain good supplier relationships.

E-Invoice Requirements in FY 2026-27

E-invoicing under GST is no longer optional for medium and large businesses. If your aggregate turnover exceeded ₹5 crore in any financial year from 2017-18 onward, you must generate e-invoices for all B2B supplies. This threshold has been progressively lowered from ₹500 crore (when e-invoicing launched in October 2020) to the current ₹5 crore limit.

How E-Invoicing Works

Every B2B invoice must be reported to the Invoice Registration Portal (IRP) before it is issued to the buyer. The IRP validates the invoice data, generates a unique Invoice Reference Number (IRN) and a QR code, and returns the signed invoice to the supplier. The invoice is then auto-populated in your GSTR-1, eliminating manual data entry for outward supplies. Your buyers also see the invoice reflected in their GSTR-2B for ITC claims.

Key Compliance Points for FY 2026-27

• Threshold: ₹5 crore aggregate turnover in any FY from 2017-18 onward
• Applicability: All B2B invoices, including export invoices and supplies to SEZs
• Exemptions: B2C invoices, import transactions, and supplies by SEZ units to DTA
• Time limit: E-invoices must be generated within 30 days of the invoice date (for taxpayers with turnover above ₹100 crore)
• Penalty for non-compliance: Invoice treated as invalid; buyer cannot claim ITC; penalty of ₹10,000 or 100% of tax due, whichever is higher, under Section 122 of the CGST Act

If your Private Limited Company or LLP crossed the ₹5 crore turnover mark in any year since GST inception, ensure your invoicing software supports IRP integration. Most accounting platforms like Tally, Zoho Books, and ClearTax have built-in e-invoice modules.

GST Return Filing Categories: Who Files What

Not every GST-registered business files the same set of returns. Your filing obligations depend on your registration type, turnover, and business model. Here is a clear breakdown by taxpayer category so you can identify exactly which returns apply to you in FY 2026-27.

A typical Private Limited Company with turnover between ₹2 crore and ₹5 crore files 24 monthly returns (12 GSTR-1 + 12 GSTR-3B) plus 1 annual GSTR-9, totaling 25 filings per year. Opting for QRMP reduces this to 8 quarterly returns plus 8 PMT-06 payments - fewer filings, same tax obligation. For a sole proprietorship with turnover under ₹2 crore on QRMP, the count drops to just 8 returns with no annual return requirement.

Late Filing Penalties and Interest Under GST

GST penalties are automatic. The moment you miss a due date, late fees begin accumulating on the portal. There is no grace period, no warning email, and no manual trigger required. Understanding the exact penalty structure helps you prioritize filings when cash flow is tight.

Late Fee Structure by Return Type

Interest on Unpaid Tax

Beyond late fees, interest at 18% per annum applies on the outstanding tax amount from the due date until the date of actual payment. If you claimed excess ITC, interest of 24% per annum applies on the excess amount. Interest is calculated on a daily basis and adds up quickly. For example, if you owe ₹1,00,000 in tax and file 30 days late, the interest alone is approximately ₹1,479 (₹1,00,000 x 18% x 30/365).

Consequences Beyond Penalties

Late filing does not just cost money. It triggers a cascade of compliance problems. Your buyers cannot claim ITC on invoices reported in a delayed GSTR-1. Continued non-filing for 2 or more consecutive months (for monthly filers) or 2 consecutive quarters (for QRMP filers) can result in suo motu cancellation of your GST registration by the tax officer. Reinstating a cancelled registration requires filing all pending returns with full late fees and interest, plus an application for revocation within 30 days of cancellation.

Quarter-Wise GST Compliance Summary for FY 2026-27

For a quick reference view, here is the quarterly breakdown of major deadlines. This is especially useful for business owners who plan compliance activities at the start of each quarter.

Q1: April-June 2026

• Monthly filers: 3x GSTR-1 (May 11, Jun 11, Jul 11), 3x GSTR-3B (May 20, Jun 20, Jul 20)
• QRMP filers: 2x IFF (May 13, Jun 13), 2x PMT-06 (May 25, Jun 25), 1x GSTR-1 (Jul 13), 1x GSTR-3B (Jul 22/24)
• Composition dealers: 1x CMP-08 (Jul 18)
• TDS/TCS deductors: 3x GSTR-7/GSTR-8 (May 10, Jun 10, Jul 10)

Q2: July-September 2026

• Monthly filers: 3x GSTR-1 (Aug 11, Sep 11, Oct 11), 3x GSTR-3B (Aug 20, Sep 20, Oct 20)
• QRMP filers: 2x IFF (Aug 13, Sep 13), 2x PMT-06 (Aug 25, Sep 25), 1x GSTR-1 (Oct 13), 1x GSTR-3B (Oct 22/24)
• Composition dealers: 1x CMP-08 (Oct 18)
• TDS/TCS deductors: 3x GSTR-7/GSTR-8 (Aug 10, Sep 10, Oct 10)

Q3: October-December 2026

• Monthly filers: 3x GSTR-1 (Nov 11, Dec 11, Jan 11), 3x GSTR-3B (Nov 20, Dec 20, Jan 20)
• QRMP filers: 2x IFF (Nov 13, Dec 13), 2x PMT-06 (Nov 25, Dec 25), 1x GSTR-1 (Jan 13), 1x GSTR-3B (Jan 22/24)
• Composition dealers: 1x CMP-08 (Jan 18)
• TDS/TCS deductors: 3x GSTR-7/GSTR-8 (Nov 10, Dec 10, Jan 10)

Q4: January-March 2027

• Monthly filers: 3x GSTR-1 (Feb 11, Mar 11, Apr 11), 3x GSTR-3B (Feb 20, Mar 20, Apr 20)
• QRMP filers: 2x IFF (Feb 13, Mar 13), 2x PMT-06 (Feb 25, Mar 25), 1x GSTR-1 (Apr 13), 1x GSTR-3B (Apr 22/24)
• Composition dealers: 1x CMP-08 (Apr 18)
• TDS/TCS deductors: 3x GSTR-7/GSTR-8 (Feb 10, Mar 10, Apr 10)

Annual Deadlines (FY 2026-27)

• GSTR-9 (Annual Return): December 31, 2027 - mandatory for turnover above ₹2 crore
• GSTR-9C (Reconciliation): December 31, 2027 - mandatory for turnover above ₹5 crore
• GSTR-4 (Composition Annual): April 30, 2028 - for composition scheme dealers

PMT-06: Monthly Tax Payment Under QRMP Scheme

The PMT-06 challan is the mechanism through which QRMP scheme taxpayers pay their monthly GST liability without filing a full return. It applies only to the first two months of each quarter - the third month's tax is settled through the quarterly GSTR-3B filing.

Payment Methods

The GST portal offers two methods for calculating your PMT-06 payment:

1. Fixed Sum Method (Pre-filled): The portal auto-calculates 35% of the net tax paid in the GSTR-3B of the previous quarter. This amount is pre-populated in PMT-06. You simply verify and pay. This is the easiest option for businesses with stable monthly sales. However, if your current month's liability is significantly higher than 35% of the previous quarter, you may face a shortfall and owe interest on the difference.

2. Self-Assessment Method: You calculate your actual liability for the month based on outward supplies minus eligible ITC, and pay the exact amount. This requires up-to-date bookkeeping but avoids over-payment or under-payment. Businesses with seasonal sales variations should prefer this method.

PMT-06 Due Dates for FY 2026-27

• April 2026 → May 25, 2026
• May 2026 → June 25, 2026
• July 2026 → August 25, 2026
• August 2026 → September 25, 2026
• October 2026 → November 25, 2026
• November 2026 → December 25, 2026
• January 2027 → February 25, 2027
• February 2027 → March 25, 2027

No PMT-06 is required for June 2026, September 2026, December 2026, and March 2027 - these are the third months of each quarter, and tax for these months is paid via the quarterly GSTR-3B.

Annual GST Returns: GSTR-9 and GSTR-9C Explained

Annual returns are the year-end reconciliation between your monthly/quarterly filings and your actual books of accounts. Getting these right avoids scrutiny notices and ensures your ITC claims are properly reconciled.

GSTR-9: The Annual Return

GSTR-9 consolidates all the data from your GSTR-1 and GSTR-3B filings for the entire financial year. It covers outward supplies, inward supplies, ITC claimed, tax paid, and any amendments made during the year. For FY 2026-27, the due date is December 31, 2027. It is mandatory for regular taxpayers with aggregate turnover exceeding ₹2 crore. Taxpayers with turnover up to ₹2 crore are currently exempt, though this exemption is subject to annual government notification.

Filing GSTR-9 requires careful reconciliation. Common discrepancies include differences between GSTR-1 outward supply values and books, mismatches between GSTR-3B ITC claims and GSTR-2B auto-populated ITC, and tax payment timing differences. Start the reconciliation process at least 2 months before the deadline to avoid last-minute corrections.

GSTR-9C: Reconciliation Statement

GSTR-9C is a self-certified reconciliation between GSTR-9 data and your audited annual financial statements. It is mandatory only for taxpayers with aggregate turnover exceeding ₹5 crore. Since FY 2020-21, CA certification is no longer required - the taxpayer self-certifies the reconciliation. The due date is the same as GSTR-9: December 31, 2027 for FY 2026-27.

The reconciliation covers turnover as per books vs turnover reported in GSTR-9, ITC as per books vs ITC claimed in returns, and tax paid vs tax liability. If discrepancies exceed prescribed limits, additional tax must be paid through DRC-03 before filing GSTR-9C. Businesses with Virtual CFO support typically complete this reconciliation faster because their books are maintained monthly rather than compiled at year-end.

How to Set Up GST Compliance Reminders

Knowing the deadlines is half the battle. The other half is ensuring you act on them before they pass. Are you relying on memory or a shared spreadsheet that nobody updates? Here is a systematic approach to building a reminder system that actually works.

Method 1: Google Calendar / Outlook Recurring Events

Create recurring calendar events for each return type with alerts set 3 days before the due date. For FY 2026-27, set up these recurring events:

• GSTR-1: Monthly recurring on the 8th (3 days before the 11th due date)
• GSTR-3B: Monthly recurring on the 17th (3 days before the 20th due date)
• GSTR-7/GSTR-8: Monthly recurring on the 7th (3 days before the 10th due date)
• CMP-08: Quarterly recurring on the 15th of Jan, Apr, Jul, Oct
• PMT-06 (QRMP): Monthly recurring on the 22nd (3 days before the 25th due date)
• GSTR-9: Single event on December 15, 2027 (2 weeks before deadline)

Method 2: Accounting Software Alerts

Most modern accounting platforms - Tally Prime, Zoho Books, ClearTax, and Busy Accounting - have built-in GST due date trackers. Enable push notifications and email alerts. If you use professional GST filing services, your service provider typically manages deadline tracking on your behalf.

Method 3: Compliance Checklist Spreadsheet

For businesses that prefer a manual tracking approach, create a spreadsheet with columns for: Tax Period, Return Type, Due Date, Filing Status (Pending/Filed), Filing Date, ARN Number, and Late Fee (if any). Update it after every filing. Share it with your accountant and business partners for accountability. The discipline of marking each filing as complete creates a reliable audit trail.

Common GST Compliance Mistakes to Avoid in FY 2026-27

After assisting hundreds of businesses with GST compliance, these are the errors we see most frequently. Each one is avoidable with basic process discipline.

• Filing GSTR-3B before GSTR-1: Always file GSTR-1 first. The outward supply data in GSTR-1 feeds into your buyer's GSTR-2B. Filing GSTR-3B first does not upload invoice data, and your buyers lose ITC visibility.
• Ignoring GSTR-2B reconciliation: Before filing GSTR-3B, match your purchase register with the GSTR-2B auto-populated ITC. Claiming ITC not reflected in GSTR-2B triggers notices during assessment.
• Missing IFF uploads under QRMP: If you are on the QRMP scheme and have B2B buyers, not uploading invoices via IFF means your buyers wait an entire quarter to claim ITC on your invoices. This strains supplier relationships.
• Not paying via PMT-06: QRMP taxpayers must pay tax monthly even though they file quarterly. Skipping PMT-06 results in interest liability that surfaces when you file your quarterly GSTR-3B.
• Incorrect GSTIN on e-invoices: A single digit error in the buyer's GSTIN on an e-invoice means the IRN is generated for the wrong entity. The buyer cannot claim ITC, and you need to issue a credit note and re-generate the invoice.
• Delaying annual return preparation: Do not wait until November 2027 to start GSTR-9 reconciliation. Begin quarterly reconciliation of GSTR-1, GSTR-3B, and your books. This spreads the workload and catches discrepancies early.
• Forgetting reverse charge obligations: Services received from unregistered suppliers above the threshold, legal services, and certain notified services attract reverse charge. These must be reported in GSTR-3B even if no invoice was received from the supplier.
• Not updating registration details: Changed your business address, added a new business vertical, or appointed a new director? Update your GST registration within 15 days of the change. Outdated registration details invite scrutiny.

Summary

The GST compliance calendar for FY 2026-27 requires attention to 24+ deadlines for monthly filers, 8 return filings plus 8 payment dates for QRMP participants, and 4 quarterly statements for composition dealers - all before the annual return deadline of December 31, 2027. GSTR-1 is due on the 11th, GSTR-3B on the 20th, GSTR-7 and GSTR-8 on the 10th, and PMT-06 on the 25th of the following month. E-invoicing is mandatory for turnover above ₹5 crore. Late fees start at ₹50 per day with 18% annual interest on unpaid tax. The most effective compliance strategy is simple: file GSTR-1 before GSTR-3B, reconcile GSTR-2B monthly, pay via PMT-06 on time if you are on QRMP, and start GSTR-9 preparation at least 2 months before the deadline. Use calendar reminders, accounting software alerts, or a professional GST return filing service to stay on track. Missing a deadline is never worth the penalty.