October is an important month for businesses, accountants and finance teams in India. With monthly GST returns, quarterly tax statements and income-tax audit obligations falling due, staying organised is essential to avoid last-minute filing pressure and preventable compliance errors.

Missing a deadline can lead to late fees, interest or other consequences, depending on the applicable law and the nature of the default. Businesses should therefore review their compliance calendars early, reconcile their financial records and ensure that the required returns and payments are completed within the prescribed timelines.

One of the key developments this month is the extension of the specified tax audit-report deadline for Assessment Year (AY) 2026–27 to 21 October 2026, with the corresponding ITR deadline extended to 21 November 2026 for the covered category. Alongside this change, several GST and TDS/TCS obligations require attention throughout October.

October 2026 Tax Compliance Calendar at a Glance

The following table highlights important compliance dates for October 2026. The applicable obligations depend on the taxpayer's category, filing frequency and relevant statutory provisions.

Note: This is a general calendar, not an exhaustive list of every statutory obligation. Verify the applicable due date and any extensions before filing.

Income Tax Audit Deadline Extended to 21 October 2026

One of the most significant income-tax updates for October is the extension of the specified audit-report deadline for AY 2026–27.

Under CBDT Circular No. 07/2026 dated 28 September 2026, the due date for specified audit reports was extended from 30 September 2026 to 21 October 2026 for the category covered by the circular.

The corresponding income-tax return filing deadline for that category has been extended from 31 October 2026 to 21 November 2026.

This extension is particularly relevant for eligible businesses, professionals and other taxpayers who are required to submit audit reports under the applicable provisions. However, it should not be interpreted as a blanket extension for all taxpayers or every audit-related obligation.

Businesses should use the additional time to finalise their books, reconcile bank statements, review expenses and income, verify tax-related adjustments and coordinate with their auditors. Completing these tasks early can help reduce reporting errors and avoid a last-minute rush.

TDS and TCS Compliance: Deposit and Quarterly Reporting

Tax Deducted at Source (TDS) and Tax Collected at Source (TCS) are important responsibilities for businesses making specified payments or collecting tax on covered transactions.

For applicable deductors and collectors, 7 October 2026 is the general deadline for depositing TDS/TCS relating to September 2026, subject to the rules governing the particular transaction.

The quarterly reporting cycle also falls due at the end of October. Applicable TDS/TCS statements for the July–September 2026 quarter should generally be filed by 31 October 2026 under the relevant framework.

Before submitting statements, businesses should verify deductee or collectee details, PAN information, transaction classifications, applicable rates, challan details and tax deposits. Reconciliation between the accounting ledger and the tax statement is particularly important because incorrect reporting can create credit mismatches for the other party.

A structured process for recording deductions, making deposits and preparing statements can help finance teams manage these responsibilities more efficiently.

GST Return Filing Deadlines for October 2026

GST compliance remains a recurring responsibility for registered businesses. The applicable forms and deadlines vary depending on whether a taxpayer files monthly or quarterly and the nature of its registration.

GSTR-1: 11 and 13 October

Monthly GSTR-1 filers should generally submit details of outward supplies for September 2026 by 11 October. Eligible quarterly filers under the QRMP scheme should generally file their July–September 2026 quarterly GSTR-1 by 13 October.

Businesses should review their sales registers, tax invoices, credit notes, debit notes, customer GSTINs and e-invoice data, where applicable, before filing.

GSTR-7 and GSTR-8: 10 October

GSTR-7 applies to persons required to deduct GST TDS, while GSTR-8 applies to eligible e-commerce operators required to collect GST TCS.

For September 2026, these statements are generally due on 10 October. The reported amounts should be reconciled with the underlying transactions and the applicable tax records before submission.

GSTR-6: 13 October

Input Service Distributors should generally file GSTR-6 for September 2026 by 13 October. They should verify eligible input-service invoices, credit notes and the distribution of input tax credit before filing.

CMP-08: 18 October

Eligible taxpayers under the GST composition scheme should generally submit CMP-08 for the July–September 2026 quarter by 18 October.

They should check quarterly turnover, the applicable tax calculation and any relevant reverse-charge liability before submitting the statement and making the required payment.

GSTR-3B: 20 October

Monthly GST filers should generally submit GSTR-3B for September 2026 by 20 October.

Before filing, businesses should reconcile output-tax liability with their books, review eligible input tax credit, check GSTR-2B against purchase records and verify any ITC reversals or reverse-charge liabilities.

Accurate reconciliation can help prevent reporting discrepancies and support more reliable financial records.

Other GST obligations

Certain taxpayers may also need to review GSTR-5, GSTR-5A, PMT-06 and GSTR-11, depending on their status and applicable filing requirements. For QRMP taxpayers, quarterly GSTR-3B deadlines can vary by state or Union Territory, so the relevant date should be checked separately.

Other Important Compliance Dates in October

In addition to regular GST returns and TDS/TCS obligations, some businesses have specialised reporting requirements.

Specified income-tax statements for the quarter ended 30 September may fall due on 15 October for applicable categories. The 30 October deadline may also be relevant for specified challan-cum-statements.

These requirements do not apply uniformly to every business. Companies, LLPs, financial institutions and other regulated entities may also have separate filing obligations under their respective laws.

Finance teams should identify the forms relevant to their organisation instead of relying solely on a general tax calendar.

How Businesses Can Avoid Last-Minute Compliance Errors

A tax compliance calendar is most effective when it is supported by an organised accounting process. Simply knowing the due dates is not enough if financial records, invoices and tax ledgers are incomplete.

Businesses can improve compliance by maintaining a central calendar of monthly, quarterly and annual obligations. Assigning responsibility for each return, setting internal deadlines before statutory due dates and tracking filing acknowledgements can make the process more predictable.

Regular bank reconciliation, review of purchase and sales registers, verification of GST input tax credit and matching of TDS/TCS challans should be part of the routine accounting cycle. Businesses should also keep supporting documents accessible in case a return requires correction or a tax authority requests clarification.

Finally, taxpayers should monitor official notifications and portal updates. Due dates may be extended or requirements may differ for specific categories, making verification essential before filing.

Conclusion

October 2026 brings several important tax compliance responsibilities across income tax, TDS/TCS and GST. From the 7 October tax deposit deadline to monthly GST returns, quarterly statements and the specified tax audit-report deadline on 21 October, businesses need a clear plan to manage their obligations.

The extension of the covered ITR deadline to 21 November provides additional time for eligible taxpayers, but it does not remove the need to complete audit work and maintain accurate financial records.

For businesses, the best approach is to plan ahead, reconcile records regularly and verify the applicable filing requirements. A well-maintained compliance calendar helps reduce avoidable errors, supports better financial management and allows business owners to focus more confidently on growth.

At WiseBooks, we believe that organised accounting and proactive compliance are essential to building a financially stronger business.