Income tax calendar 2026: All important tax deadlines from August to December taxpayers should know

The July 31 deadline may have passed, but taxpayers are not done with their income-tax compliances for 2026.

There are a number of significant tax deadlines that fall between August and December, depending on your income, occupation, and method of earning. These include the deadline for filing an ITR for taxpayers whose accounts need to be audited, advance-tax installments, tax audit reports, and the deadline for filing a delayed return for Assessment Year (AY) 2026-2027.

The Income Tax Department has also made it clear that, despite the fact that the new Income Tax Act, 2025 went into effect on April 1, 2026, the return for income received during FY 2025-26 is still subject to the Income Tax Act, 1961 and is filed for AY 2026-27. Here are the dates you should keep an eye on

For salaried taxpayers and other individuals who have already filed their returns, this deadline may not apply. It is particularly relevant to taxpayers whose category has a later due date.

September 15 is an important date for taxpayers liable to pay advance tax.

By this date, taxpayers generally need to have paid 45% of their estimated annual advance-tax liability cumulatively.

Taxpayers whose accounts are required to be audited have another important deadline on September 30.

The Income Tax Department has confirmed that the tax audit report for FY 2025-26 (AY 2026-27) is due by September 30, 2026 for taxpayers whose corresponding ITR filing deadline is October 31.

For taxpayers whose accounts are subject to tax audit, the ITR filing deadline is generally October 31, 2026.

This deadline is different from the one applicable to taxpayers who do not require an audit, so taxpayers should check which category they fall under before assuming that the same ITR deadline applies to everyone.

October 31 is also an important date for certain TDS and TCS reporting requirements for the July-September quarter.

The Income Tax Department says the tax audit report for transfer-pricing cases is due by October 31, while the corresponding ITR filing deadline is November 30, 2026.

December 15 is the next major advance-tax deadline.

By this date, taxpayers generally need to have paid 75% of their estimated annual advance-tax liability cumulatively.

For people with significant income from sources such as business, professional fees, capital gains, interest or other non-salary income, keeping track of advance-tax payments is particularly important.

What about a revised ITR?

This is where taxpayers need to be careful. December 31 is not the general last date for filing a revised return for AY 2026-27

The Income Tax Department has clarified that a revised return for AY 2026-27 can be filed under the Income Tax Act, 1961 before the end of the relevant assessment year, March 31, 2027, or before completion of assessment, whichever is earlier, subject to the applicable provisions.

So, while December 31 is an important deadline for a belated return, taxpayers who have already filed their ITR and later discover an error should not confuse the belated-return deadline with the revised-return timeline.