Comprehensive Section Mapping Guide: Transitioning from Income-tax Act, 1961 to Income-tax Act, 2025

Beginning April 1, 2026, the direct tax landscape in India will undergo a historic transformation as the Income-tax Act, 2025 officially supersedes the legacy Income-tax Act, 1961. This legislative overhaul brings forth a highly streamlined framework, dramatically reducing the volume of statutory provisions. The total number of sections has been slashed from 819 to a leaner 536, while the structural chapters have been compressed from 47 down to 23.

Despite this massive reorganization, the foundational tax rates and income slabs remain entirely untouched. However, the nomenclature and numbering of almost every familiar provision have been altered. For any assessee, chartered accountant, or legal professional accustomed to citing legacy provisions by memory, this transition demands a complete mental reset. This comprehensive guide serves as a critical mapping tool, translating the most frequently invoked provisions of the old regime into their new statutory homes under the Income-tax Act, 2025.

A crucial challenge during the initial phase of implementation is that both statutes will operate simultaneously, albeit for completely different timeframes. Understanding which Act applies to which period is paramount to avoid critical errors in compliance and litigation.

  • **For FY 2025-26 (AY 2026-27)😗* All tax returns, assessments, and related compliance will continue to be strictly governed by the Income-tax Act, 1961.
  • For Tax Year 2026-27 Onwards: Any income generated, advance tax paid, or TDS deducted from this period forward will fall exclusively under the jurisdiction of the Income-tax Act, 2025.
  • Legacy Proceedings: All ongoing appeals, reassessments, and scrutiny proceedings pertaining to earlier years will remain anchored to the 1961 Act.

Important Note: The Income-tax Act, 2025 introduces a paradigm shift by eliminating the dual concepts of "previous year" and "assessment year." Under Section 3 of the new Act, these have been consolidated into a singular, unified concept known as the "Tax Year." Citing a new section number while responding to a departmental notice for AY 2026-27 or earlier is a procedural misstep that every assessee and practitioner must actively avoid.

The Most Critical Section Mappings

To facilitate a smooth transition, we have categorized the most vital statutory shifts that will impact daily tax practice.

1. Foundational Concepts and Exemptions

The fundamental building blocks of income computation have been rehoused.

  • The definition of the financial period under Section 3 remains Section 3 (now termed Tax Year).
  • General exempt incomes, previously clustered under Section 10 (such as House Rent Allowance), are now governed by Section 11, which must be read in conjunction with Schedules II through VII.
  • The standard deduction applicable to salaried individuals has shifted from Section 16 to Section 19.