The ITR due date for FY 2024-25 (AY 2025-26) is September 15, 2025, after a CBDT extension from July 31 due to new forms and system updates. Miss it and you face a late fee of up to Rs 5,000 plus 1% monthly interest on unpaid tax. Belated and revised returns are allowed till December 31, 2025. Audit and transfer pricing cases have later dates, and updated returns are allowed until March 31, 2030.