Under section 3(1) of the Income-tax Act, 2025, "tax year" means

Section 3(1) defines "tax year" as "the twelve months period of the financial year commencing on the 1st April". The year following the year of earning describes the old assessment-year idea, which the 2025 Act does not use. Section 3(2) shortens only the first tax year of a new business, profession or source of income; the assessee cannot choose his own accounting year.