GST Calendar for October 2025: Key Due Dates and Compliance Guide

For Chartered Accountants, tax consultants, and compliance officers, staying ahead of deadlines is half the battle in GST compliance.

A missed date can mean late fees, penalties, interest, and strained client relationships. That is where the GST Calendar for October 2025 becomes essential.

This blog provides a comprehensive guide to all GST due dates in October 2025, practical tips for managing multiple filings, and strategies to avoid last-minute compliance headaches.

Whether you manage monthly filers, quarterly filers under the QRMP scheme, or composition taxpayers, this calendar ensures you have a clear roadmap for the month.

Understanding GST Returns and Payment Structure

Monthly, Quarterly, and Special Returns

Before looking at the dates, it’s important to recall the GST return types that apply across different taxpayers:

• GSTR-1: Monthly/quarterly statement of outward supplies.
• GSTR-3B: Monthly/quarterly summary return with tax payment.
• QRMP Scheme: Quarterly GSTR-1 and GSTR-3B, with monthly PMT-06 payments.
• CMP-08: Quarterly statement for composition taxpayers.
• GSTR-5 / GSTR-6: Returns for non-resident taxpayers and Input Service Distributors.
• GSTR-7 / GSTR-8: TDS and TCS returns for deductors and e-commerce operators.

Turnover Thresholds and Applicability

• Above ₹5 crore turnover: Monthly filing of GSTR-1 and GSTR-3B is mandatory.
• Up to ₹5 crore turnover: Eligible for the QRMP scheme.
• Composition taxpayers: File CMP-08 quarterly, with annual GSTR-4.

Correct classification is crucial early in the financial year to avoid mismatches, double filings, or penalties.

GST Calendar for October 2025: Key Due Dates

Here is the complete list of GST due dates for October 2025:

Date	Return / Form	Applicability & Details
10 October 2025	GSTR-7 & GSTR-8	TDS (tax deducted at source) and TCS (tax collected at source) returns for September 2025
11 October 2025	GSTR-1 (Monthly)	Outward supplies for September 2025 (monthly filers with turnover > ₹5 crore)
13 October 2025	GSTR-5 & GSTR-6	Non-resident taxable persons and Input Service Distributors for September 2025
18 October 2025	CMP-08	Composition taxpayers: Quarterly return for July–September 2025
20 October 2025	GSTR-3B (Monthly)	Summary return and payment for September 2025 (monthly filers)
22 October 2025	GSTR-3B (Quarterly)	QRMP scheme return for July–September 2025 (Category X states)
24 October 2025	GSTR-3B (Quarterly)	QRMP scheme return for July–September 2025 (Category Y states)
25 October 2025	PMT-06	Monthly tax payment for QRMP filers (if liability arises)

Important Notes

• The QRMP scheme divides states into Category X and Category Y with staggered deadlines.
• PMT-06 is mandatory for QRMP taxpayers who owe tax in the first two months of the quarter.
• Deadlines may shift if the CBIC announces extensions; always verify near the due date.

Practical Insights for Tax Professionals

1. Build a Compliance Dashboard

• Set calendar alerts for 10th, 11th, 13th, 18th, 20th, 22nd/24th, and 25th October.
• Automate reminders via workflow or practice management software.
• Use a firm-wide tracker to reduce dependency on manual follow-ups.

2. Manage Mixed Client Portfolios

Tax professionals often handle clients with different filing frequencies. Some may be on monthly GSTR-1 and 3B, while others use the QRMP scheme.

• Segregate clients into filing categories.
• Pre-schedule the collection of invoices and credit notes accordingly.
• For businesses crossing the ₹5 crore turnover threshold mid-year, ensure a smooth shift from quarterly to monthly returns.

3. Reduce Late Filing Risks

• Close books at least five days before the due date.
• Maintain a buffer fund for tax payments.
• Follow a two-step deadline approach: internal “soft deadline” + statutory deadline.

4. Strengthen Client Communication

• Share this GST calendar for October 2025 with clients in advance.
• Clearly outline document requirements (invoices, ITC proofs, debit/credit notes).
• Use standardized templates for data requests to avoid delays.

5. Stay Updated on Notifications

• Regularly monitor the GST portal and CBIC circulars.
• Subscribe to update alerts to catch extensions, late fee waivers, or clarifications.
• Incorporate changes into your compliance tracker in real time.

Challenges and Risk Areas in October 2025

• Cluttered mid-month: Multiple deadlines from 10–13 October may overwhelm small teams.
• QRMP confusion: Misunderstanding state categorization (X vs. Y) can lead to missed filings.
• Turnover volatility: Clients moving between quarterly and monthly filing mid-year.
• Client dependency: Late submission of records creates last-minute bottlenecks.
• Portal slowdowns: High traffic on the GSTN portal near due dates.

Compliance Checklist for October 2025

• Verify client turnover classification (monthly/quarterly/composition).
• Set reminders for 10th, 11th, 13th, 18th, 20th, 22nd/24th, and 25th October.
• Collect invoices, credit notes, ISD allocations, and TDS/TCS details.
• Prepare and review draft returns for errors.
• Ensure tax payments are ready under PMT-06 or GSTR-3B.
• Record compliance in an audit-ready tracker.
• Monitor CBIC updates until the last filing day.

The GST Calendar for October 2025 is not just a checklist of dates, it is a compliance strategy. By proactively tracking due dates, coordinating with clients, and leveraging automation tools, tax professionals can minimize risks, ensure timely filing, and avoid costly penalties.

In an increasingly regulated environment, discipline around GST due dates is what separates efficient tax practices from reactive ones. Start preparing today, and let October 2025 be a month of smooth, penalty-free compliance.

FAQs

1. What are the important GST due dates in October 2025?

The important GST due dates include GSTR-7 and GSTR-8 (10 Oct), GSTR-1 (11 Oct), GSTR-5 and GSTR-6 (13 Oct), CMP-08 (18 Oct), GSTR-3B monthly (20 Oct), GSTR-3B quarterly for QRMP filers (22/24 Oct), and PMT-06 (25 Oct).

2. How do I know if my client should file GST returns monthly or quarterly?

Clients with turnover above ₹5 crore must file GSTR-1 and GSTR-3B monthly. Those with turnover up to ₹5 crore can opt for the QRMP scheme, filing quarterly returns with monthly PMT-06 payments if liability arises.

3. What happens if GST returns for October 2025 are filed late?

Late filing attracts late fees, interest on unpaid tax, and in some cases, blocks ITC for recipients. Consistent delays may also trigger GST compliance scrutiny.

4. Do QRMP filers need to pay tax every month in October 2025?

Yes, QRMP filers must use PMT-06 to pay tax for the first two months of the quarter, including October if liability exists. The GSTR-3B return is filed quarterly.