Income Tax Deadlines: 8 Key Dates from August to December 2026

November 30 is the due date for filing the return of income for taxpayers who must furnish a tax audit report. That includes businesses, professionals, and others whose accounts must be audited.

December 15 is the third advance tax installment. Cumulative payment must reach 75% of the estimated annual tax. The penalty structure is the same: interest at 1% per month on the unpaid amount.

December 31 is the last date to file a belated return for Assessment Year 2026-27. This applies to any taxpayer who missed the regular July 31 or November 30 due dates. A belated return carries a fee under Section 234F – ₹5,000 for most filers, ₹1,000 for those with total income up to ₹5 lakh.

Taxpayers who discover errors in their filed return can file a revised return until March 31, 2027, or before the completion of assessment, whichever is earlier. The revised return deadline is separate from the belated return deadline.

The Income-tax Act, 2025 came into force on April 1, 2026. It introduced the concept of a single 'Tax Year', replacing the old dual system of 'Previous Year' and 'Assessment Year'. For Assessment Year 2026-27, the income relates to Financial Year 2025-26, and the old Act still governs the computation. The new Act applies from Tax Year 2026-27 onward.

Taxpayers should check the official Income Tax website for the exact deadline relevant to their audit status and income category. The dates above apply to specific classes and may shift slightly based on government notifications.