The single tax year under the 2025 Act, the filing deadlines, and the end of assessment-year language
From tax year 2026-27 the Income-tax Act 2025 is in force, and it replaces the old pair of terms (previous year and assessment year) with a single tax year, the twelve months from 1 April to 31 March in which you earn. So 2026-27 means income earned between 1 April 2026 and 31 March 2027, and you file the return for it after the year ends. For most self-employed people the return is due by 31 July following the year end; where a tax audit applies it is 31 October. Miss those and you can still file a belated or revised return up to 31 December, and an updated return (ITR-U) for longer.
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One tax year, not two confusing terms
Under the old Income-tax Act 1961 you had to juggle two terms: the previous year (when you earned) and the assessment year (the following year, when the income was assessed). The Income-tax Act 2025, in force from tax year 2026-27, drops that and uses a single tax year, the financial year from 1 April to 31 March in which the income arises. This is a presentational simplification, not a change to when income is taxed: you still earn through the year and file after it ends.
The dates that matter
The deadlines run from the end of the tax year. Most are the same for everyone; the audit and transfer-pricing dates are later.
Key dates for tax year 2026-27 (returns filed in 2027)
Event
Date
Tax year
1 April 2026 to 31 March 2027
Return due (non-audit, most self-employed)
31 July 2027
Return due (tax-audit cases)
31 October 2027
Return due (transfer-pricing cases)
30 November 2027
Belated or revised return
31 December 2027
Updated return (ITR-U)
Up to 48 months after the tax year end
tipIf you are on presumptive taxation (44AD/44ADA) and within the limits, you are usually outside the audit requirement, so your return is the 31 July one, not the 31 October audit date.
What actually changed, and what did not
The 2025 Act renumbers and consolidates the law and changes the terminology, but the core 2026-27 figures (the Rs 4 lakh basic exemption, the Rs 60,000 rebate making income up to Rs 12 lakh tax-free, the new-regime slabs, presumptive rates, GST thresholds) are set by the finance acts and are unchanged by the renumbering. Where this site cites a section, it gives the 1961 Act number with the 2025 Act number alongside, so older references still make sense.
warningOld articles still say assessment year 2027-28 for income earned in 2026-27. That is the same period under the old naming. Match the tax year to when you earned, not to the assessment-year label.
Income-tax Act 1961 s.139(1) (return due dates; re-enacted in the Income-tax Act 2025)
Income-tax Act 1961 s.139(4)/(5) (belated and revised returns)
Frequently asked questions
What does tax year 2026-27 mean?+
It is the period from 1 April 2026 to 31 March 2027, the twelve months in which you earn. Under the Income-tax Act 2025 this single tax year replaces the old previous-year and assessment-year pair. You file the return for 2026-27 after 31 March 2027, normally by 31 July 2027.
When is my income-tax return due?+
For most self-employed people without a tax audit, 31 July following the tax year (31 July 2027 for 2026-27). Where a tax audit applies, it is 31 October, and transfer-pricing cases are 30 November. If you miss the date you can still file a belated or revised return up to 31 December.
Has the assessment year been abolished?+
The term has. The Income-tax Act 2025, in force from tax year 2026-27, uses a single tax year instead of the old previous-year and assessment-year pair. The period is the same; only the label changed. Older content referring to assessment year 2027-28 means income earned in tax year 2026-27.
Did the 2025 Act change the tax rates?+
No. The 2025 Act renumbers and reorganises the law and changes the terminology, but the rates, slabs, exemptions and thresholds for 2026-27 (Rs 4 lakh basic exemption, Rs 60,000 rebate, the new-regime slabs and so on) come from the finance acts and are unaffected by the renumbering.