The deadline for filing income tax returns in July has passed, but taxpayers still have several important compliance dates to keep track of between August and December 2026.
The remaining tax calendar includes deadlines for advance tax instalments, tax audit reports, income tax return filing, TDS/TCS reporting and belated ITRs. The applicable date depends on the taxpayer's income, audit requirements and other circumstances.
The Income Tax Department has also clarified the transition between the existing and new tax law frameworks. Assessment Year (AY) 2026-27 relates to income earned during FY 2025-26 and continues to be governed by the Income-tax Act, 1961, despite the new Income-tax Act, 2025 coming into force from April 1, 2026.
The new law applies from FY 2026-27 under the new 'Tax Year' concept, which replaces the earlier system of the Previous Year and Assessment Year.
Income Tax Deadlines From August To December 2026
Here are the key dates taxpayers should keep on their tax calendar:
| Date | Compliance | Who should take note |
|---|---|---|
| August 31, 2026 | ITR filing | Certain non-audit taxpayers |
| September 15, 2026 | Second advance tax instalment | Taxpayers liable to pay advance tax |
| September 30, 2026 | Tax audit report | Taxpayers whose accounts require audit |
| October 31, 2026 | ITR filing | Taxpayers subject to tax audit |
| October 31, 2026 | TDS/TCS reporting | Applicable deductors and collectors |
| November 30, 2026 | ITR filing | Certain transfer-pricing cases |
| December 15, 2026 | Third advance tax instalment | Taxpayers liable to pay advance tax |
| December 31, 2026 | Belated ITR | Taxpayers who missed their original deadline |
These dates apply to specific categories of taxpayers and can vary depending on factors such as the nature of income and audit requirements. Taxpayers should check the applicable deadline for their circumstances on the official Income Tax website before filing returns or making payments.
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September And December Advance Tax Deadlines
Taxpayers who are liable to pay advance tax have two important instalment dates coming up in the next few months.
By September 15, eligible taxpayers generally need to have paid 45 per cent of their estimated annual tax liability. The requirement rises to 75 per cent by December 15.
These instalments are particularly relevant for taxpayers receiving substantial income from sources such as professional fees, business activities, interest, capital gains or other non-salary income.
Failure to pay advance tax as required can lead to interest and other consequences under the applicable tax provisions.
December 31 Deadline For Belated ITR
Taxpayers who missed their original ITR filing deadline should also keep December 31, 2026 on their calendar.
This is the last date for filing a belated return for AY 2026-27, subject to the applicable rules and assessment status.
However, taxpayers should distinguish between a belated return and a revised return.
A taxpayer who has already submitted an ITR but subsequently discovers an error or omission may be able to file a revised return. For AY 2026-27, such a return can be filed until March 31, 2027, or before completion of assessment, whichever is earlier, subject to the applicable tax provisions.
Taxpayers Should Track The Deadline Applicable To Them
With multiple tax compliance dates falling between August and December, taxpayers should first determine which category they fall under and identify the deadlines applicable to their circumstances.
Keeping documents such as PAN, Aadhaar, a registered mobile number and other relevant records ready can also help with the filing process.
Completing the applicable compliance requirements ahead of the deadline can help taxpayers avoid last-minute errors, omissions and additional costs.