# GST CMP-08 Filing for July–September 2026: Due Date, Procedure, Eligibility and Tax Compliance

## Introduction

GST compliance is an important responsibility for businesses registered under the Goods and Services Tax system in India. Taxpayers who have opted for the GST Composition Scheme must fulfil the applicable quarterly tax payment and annual return requirements. One of the important forms for these taxpayers is GST CMP-08.

Form GST CMP-08 is used to declare self-assessed tax payable for a relevant quarter. Eligible composition taxpayers should maintain proper sales records, calculate their tax liability correctly and complete the required filing within the prescribed time limit.

For the July–September 2026 quarter, the normally applicable due date for filing GST CMP-08 is 18 October 2026, subject to any applicable government notification or extension. Taxpayers should verify the current filing status and deadline on the official GST portal before completing their compliance.

## What Is GST CMP-08?

GST CMP-08 is a quarterly statement-cum-challan prescribed under the GST framework for taxpayers paying tax under the Composition Scheme. It is used to report self-assessed tax liability and facilitate payment of the applicable tax.

Unlike the regular monthly GST return process followed by many taxpayers, composition taxpayers have a separate compliance mechanism. They generally pay tax quarterly through CMP-08 and furnish the applicable annual return in Form GSTR-4.

The purpose of CMP-08 is to provide a summary of the tax liability arising during the quarter. The taxpayer must calculate the amount payable after considering relevant transactions and adjustments permitted under the applicable provisions.

## Who Is Required to File GST CMP-08?

GST CMP-08 applies to taxpayers who are covered by the relevant composition provisions and are required to furnish the quarterly statement.

Depending on eligibility and the applicable scheme, these may include:

- Eligible small businesses and traders.

- Eligible manufacturers registered under the Composition Scheme.

- Eligible restaurants and other permitted service providers.

- Other registered persons who have validly opted for the applicable composition category.

The eligibility conditions, turnover limits, permitted activities and applicable tax rates vary according to the category of taxpayer. Therefore, a business should confirm that its registration and composition status remain valid for the relevant financial year.

Businesses operating under the regular GST scheme should not assume that CMP-08 applies to them. Their return filing and tax payment obligations may be different.

## GST CMP-08 Due Date for July–September 2026

Under the generally applicable provisions, Form GST CMP-08 is required to be furnished by the 18th day of the month following the relevant quarter.

For the quarter covering July, August and September 2026, the normal due date is 18 October 2026.

As the date falls on a Sunday, taxpayers should not automatically assume that the deadline will shift to the next working day. The applicable date should be verified against any official extension or other relevant notification.

Timely compliance helps businesses avoid unnecessary payment delays and maintain an organised record of their GST obligations.

## Important Information Required Before Filing

Before preparing CMP-08, taxpayers should collect and review the following information:

1. GSTIN and registration details.

2. Sales invoices and relevant outward supply records.

3. Details of taxable, exempt and other relevant supplies.

4. Credit notes, debit notes and amendments, wherever applicable.

5. Details of inward supplies attracting reverse charge, where applicable.

6. Previous quarter adjustments, including any relevant negative liability adjustment.

7. Tax calculations based on the applicable composition provisions.

8. Details of tax already deposited and the available electronic cash ledger balance.

Accurate records help minimise discrepancies between the business accounts and the information declared on the GST portal.

## How to File GST CMP-08 Online

The filing process can generally be completed through the official GST portal by following these steps.

**Step 1: Log in to the GST portal**

Visit the official GST portal at https://www.gst.gov.in and log in using the registered taxpayer credentials.

**Step 2: Open the Returns Dashboard**

Navigate to Services, then Returns, and select Returns Dashboard.

**Step 3: Select the financial year and quarter**

Choose the relevant financial year and the July–September 2026 tax period.

**Step 4: Open Form GST CMP-08**

Select the applicable CMP-08 filing option available for the composition taxpayer.

**Step 5: Enter the tax liability details**

Review the relevant supply values and calculate the tax payable in accordance with the applicable provisions. Include other relevant liability details, such as reverse charge and interest, where applicable.

**Step 6: Review the statement**

Check the figures against the books of accounts, sales records and supporting documents. Correct any errors before proceeding.

**Step 7: Pay the tax liability**

Deposit the applicable amount through the permitted payment mechanism. CMP-08 liabilities are discharged through the electronic cash ledger; input tax credit cannot be used to pay these liabilities.

**Step 8: File the statement**

Complete the applicable verification and filing process using the facility available on the GST portal.

**Step 9: Save the acknowledgement**

Download and preserve the filed statement and acknowledgement details for future reference.

The precise portal screens and available options may change as the GST system is updated.

## Is GST CMP-08 Mandatory Even When There Are No Sales?

Eligible taxpayers should review the filing requirement even when there is no business activity during the quarter.

According to the GSTN helpdesk guidance, CMP-08 is required for applicable quarters even when there is no self-assessed liability. Therefore, taxpayers should not assume that the absence of sales automatically removes the filing obligation.

The taxpayer should check the applicable portal functionality and complete the required compliance according to the circumstances of the registration.

## Can GST CMP-08 Be Revised After Filing?

GSTN's published guidance states that Form GST CMP-08 cannot be revised once filed. This makes verification before submission particularly important.

Before final filing, taxpayers should carefully check turnover figures, tax calculations, reverse charge liabilities, applicable adjustments and payment details.

If an error is identified after filing, the taxpayer should examine the relevant GST provisions and available correction or adjustment mechanisms for the particular situation. A correction should not be assumed to be possible through direct revision of the filed CMP-08.

## What Happens If GST CMP-08 Is Filed Late?

Late filing can create compliance concerns and may require the taxpayer to review any unpaid tax and applicable interest.

Interest may arise where tax remains unpaid beyond the legally prescribed period, depending on the facts and the applicable provisions. The calculation should be made after examining the nature of the liability, the relevant dates and the applicable statutory requirements.

GSTN's helpdesk guidance currently states that no late fee is applicable for delayed filing of CMP-08. Taxpayers should nevertheless verify the latest legal position and any subsequent changes before relying on this guidance.

The absence of a late fee does not mean that the underlying tax liability or any applicable interest can be ignored.

## Common Mistakes to Avoid While Filing CMP-08

Businesses should pay attention to the following common errors:

- Selecting the wrong financial year or quarter.

- Reporting turnover without reconciling the sales records.

- Applying an incorrect composition tax rate.

- Overlooking reverse charge liabilities.

- Ignoring relevant credit notes, debit notes or adjustments.

- Assuming that no filing is required when there are no sales.

- Attempting to use input tax credit for payment of composition tax.

- Failing to retain the acknowledgement and payment records.

- Waiting until the final day without checking portal access and payment readiness.

A systematic review before filing can help reduce avoidable errors and improve compliance management.

## Difference Between GST CMP-08 and GSTR-4

CMP-08 and GSTR-4 serve different purposes under the Composition Scheme.

CMP-08 is the quarterly statement used to declare self-assessed tax payable and facilitate payment for the relevant quarter.

GSTR-4 is the applicable annual return for composition taxpayers. It covers the relevant annual reporting requirements in accordance with the rules and instructions applicable to that financial year.

Filing CMP-08 does not automatically replace the annual GSTR-4 requirement. Taxpayers should maintain a calendar covering both quarterly and annual compliance obligations.

## Professional GST and Taxation Consultancy Services

Proper GST compliance requires accurate records, an understanding of applicable tax provisions and timely completion of filing obligations. Businesses that are uncertain about their composition status, tax calculation or filing process may seek professional assistance.

Shanky Chopra & Associates LLP provides taxation and legal consultancy services, including GST registration, GST return filing assistance, CMP-08 compliance, GST reconciliation, GST notices and replies, appeals, refunds, income tax return filing, TDS compliance and ROC-related services.

The firm serves clients in Moradabad and Kanth, Uttar Pradesh, and also assists businesses in Noida and Delhi with taxation and statutory compliance matters.

Whether a business needs help reviewing its GST records, understanding its filing obligations or preparing a response to a tax notice, professional guidance can help it understand the applicable requirements and maintain proper documentation.

## Conclusion

GST CMP-08 is an important quarterly compliance requirement for eligible taxpayers under the Composition Scheme. Businesses should review their turnover, calculate the applicable tax liability, complete the required payment and submit the statement within the prescribed time.

For the July–September 2026 quarter, the normally applicable due date is 18 October 2026, subject to official notifications or extensions. Taxpayers should confirm the latest position on the GST portal and maintain copies of their filings and payment records.

Timely preparation, accurate calculations and regular review of GST obligations can help businesses manage their compliance responsibilities more effectively.

**Contact for GST and Taxation Consultancy**

Shanky Chopra & Associates LLP  

Website: https://shankychopraassociates.in  

Phone: 9897212410 / 9084712410  

Email: advtaxgst98@gmail.com

*Disclaimer: This article is intended for general information and does not constitute legal or tax advice. Applicability of GST provisions, filing requirements and due dates should be verified against the latest official notifications, rules and GST portal instructions.*