A Practical Concordance Between the Income-tax Act, 1961 and the Income-tax Act, 2025
For over six decades, the Income-tax Act, 1961, has been the working scripture of every Indian Chartered Accountant. Section numbers became shorthand for entire bodies of jurisprudence - say "143(3)" to any practitioner and a complete picture of scrutiny assessment forms in the mind; say "68" and we think cash credits, onus, and Sumati Dayal; say "148" and we think reassessment, recorded reasons, and decades of writ litigation. These numbers were not merely identifiers. They were navigation marks in the shared cognitive map of the profession.
That map has now changed.
On 1 April 2026, the Income-tax Act, 2025 came into force, replacing the 1961 Act in its entirety. The new Act preserves the substance of direct tax law to a remarkable degree - most charging provisions, exemptions, deductions, and procedural mechanisms continue in recognisable form - but it has been renumbered, reorganised, and rewritten in plainer English. The 819 sections of the 1961 Act have been distilled into a tighter structure of 536 sections at enactment (since expanded by the Finance Act, 2026), grouped into 23 chapters and 16 schedules.
For the practitioner, this raises an immediate, unglamorous, but unavoidable question: what is the new number for the old section I have been citing for thirty years?
This article addresses that question - first by surveying the structural changes that affect daily work, then by walking through high-frequency mappings, and finally by pointing to a free open-access reference where the complete concordance is now available.
The Practical Problem No One Talks About
Press releases on the new Act dwell on simplification, modernisation, and ease of compliance. These are real benefits. But in chambers and offices across the country, the immediate problem is far more prosaic.
Appeals filed before 31 March 2026 cite section numbers from the 1961 Act. They are still pending. Written submissions, paper books, and rejoinders will continue to cite the old Act for years to come. Assessment orders being passed today may straddle both regimes - proceedings initiated under the 1961 Act, concluded under transitional provisions of the 2025 Act. Internal templates, opinion letters, audit working papers, due-diligence checklists, client communications, tax computations, and engagement letters are all written in 1961-Act vocabulary. None of this can be retired overnight.
CBDT's own mapping utility (on incometax.gov.in) is a useful starting point, but it is not designed for the way practitioners actually look things up. Most of us need to map a specific section in context, see its associated rules and circulars, and confirm whether settled jurisprudence under the old number continues to apply.
The transition, therefore, is not a clean break. It is a long overlap. For the next several years, every working CA will need to navigate both Acts simultaneously.
Structural Shifts That Affect Day-to-Day Work
Before turning to specific section mappings, three structural changes deserve mention because they affect almost every file.
First, "Tax Year" replaces "Assessment Year" and "Previous Year." The familiar distinction between the year of earning and the year of assessment has been collapsed into a single unified concept - Tax Year. For FY 2026-27, the Tax Year is simply 2026-27. There is no longer an "AY 2027-28" in the new Act's vocabulary. For ongoing matters relating to AYs up to 2025-26, the old terminology continues. Practitioners drafting fresh documents post-1 April 2026 must consciously switch terminology depending on which Act governs the matter at hand.
Second, TDS provisions have been consolidated under a single section. In the 1961 Act, TDS provisions were scattered across the high-frequency Sections 192 (salaries), 194A (interest), 194C (contractors), 194H (commission), 194I (rent), 194J (professional fees), 195 (payments to non-residents), and many others. In the 2025 Act, all TDS provisions have been brought under a single Section 393 , with the various categories appearing as tables and sub-clauses within that one section. The substance of withholding obligations is largely preserved, but the reference points have changed entirely. Citing "Section 194J" in a future TDS dispute will require translation.
Third, form numbers are due for an eventual change. Familiar forms (Form 16, Form 26AS, Form 15G/15H, Form 35, Form 36) continue for AY 2026-27 filings during the current transition window. For subsequent years, form numbering is being updated - Form 15G and 15H, for instance, are being merged into a single new Form 121. CAs should expect a second wave of nomenclature changes when these notifications are issued.
High-Frequency Mappings: A Quick Tour
Of the several hundred section-level changes, a handful affect the largest volume of practitioner work. Without attempting an exhaustive list (the complete concordance is referenced at the end of this article), a few of the highest-impact mappings are worth noting.
The unexplained-income family - old Sections 68 to 69D, covering cash credits, unexplained money, unexplained investments, unexplained expenditure, and hundi transactions - has been retained as a coherent family in the new Act and re-housed at Sections 102 to 106. The order is preserved: old Section 68 (cash credits) becomes new Section 102; old Section 69 (unexplained investments) becomes new Section 103; old Sections 69A and 69B (unexplained money and undisclosed investments) consolidate within new Section 104; old Section 69C (unexplained expenditure) becomes new Section 105; and old Section 69D (hundi transactions) becomes new Section 106. The legal principles built up through decades of case law on burden of proof, satisfactory explanation, and assessee onus continue to apply. The renumbering does not displace settled jurisprudence.
Reassessment provisions - old Sections 147, 148, 148A, 149, and 151 - have been reorganised at Sections 279 to 286 of the new Act. The mapping runs as follows: old Section 147 (income escaping assessment) becomes new Section 279; old Section 148 (notice) becomes new Section 280; old Section 148A (show-cause procedure) becomes new Section 281; old Section 149 (time limit) becomes new Section 282; and old Section 151 (sanction) becomes new Section 284. The 2021 reform structure - information-led reopening, the show-cause notice and reply mechanism before any reassessment notice, time limits tied to escaped-income thresholds, and prior approval of the specified authority - has been preserved in substance. Crucially, Section 536(2)(c) of the new Act expressly preserves the old framework for proceedings already initiated under the 1961 Act, so notices issued under the old Section 148A or Section 148 before 1 April 2026 continue to be governed by the old Act until concluded.
Charitable and religious trusts have seen one of the more conceptually significant changes in the new Act. The old framework of "charitable trusts" and "institutions" scattered across Sections 11, 12, 12A, 12AA, 12AB, 13, and 10(23C) has been consolidated into a single self-contained code at Chapter XVII-B, Sections 332 to 355. The new statutory label is Registered Non-Profit Organisation (RNPO) - the words "charitable trust" no longer appear in the registration framework itself, though the underlying definition of "charitable purpose" continues unchanged at Section 2(23) (previously Section 2(15)). Old Section 12AB (registration) maps to new Section 332; old Section 80G (donor deduction approval) maps to new Section 354. Existing 12A/12AA/12AB and 10(23C) registrations remain valid until their original expiry dates - no fresh registration is required mid-term - after which renewal must be filed under the new Section 332 framework. The familiar 85% application rule, the accumulation mechanism, and the consequences of violation all continue, now reorganised within this single chapter.
Capital gains provisions - old Sections 45 through 55A - have been preserved in substance and re-housed in the new Act's Capital Gains chapter, with the high-frequency exemptions sitting close together. The mapping for the most-used exemptions is: old Section 54 (residential house) becomes new Section 82; old Section 54B (agricultural land) becomes new Section 83; old Section 54D (compulsory acquisition) becomes new Section 84; old Section 54EC (specified bonds) becomes new Section 85; old Section 54F (residential house from non-residential asset) becomes new Section 86. The concessional rate sections are renumbered too: old Section 111A (STCG on equity) becomes new Section 196, and old Section 112A (LTCG on equity) becomes new Section 198. The JDA-specific Section 45(5A) framework, the indexation methodology, and the cost-of-acquisition rules continue substantively.
The appellate hierarchy - CIT(A)/NFAC, ITAT, High Court, Supreme Court - continues unchanged in form. Section numbers for the underlying appeal and revision provisions (old Sections 246A, 250, 251, 253, 254, 263, 264) have been updated within the new Act's procedural framework.
The pattern across the entire Act is one of structural rationalisation rather than substantive overhaul. A practitioner who knew the 1961 Act well will recognise almost every provision in the new Act - but will need a translation key for the section numbers.
A Free Reference Resource
Constructing this translation key in-house is significant work. The full Act runs to over 530 sections; the Income-tax Rules, 2026 add another 333 rules; CBDT has issued circulars and instructions that need to be cross-mapped to both old and new section numbers. For a practising firm, this is several hundred hours of careful work.
To support the profession through this transition, I have made available a free open-access reference at www.itact2025.org - a structured knowledge bank covering every section of the Income-tax Act, 2025 with verbatim statutory text and cross-references to the corresponding old-Act provision; the complete Income-tax Rules, 2026 with section linkages; CBDT circulars and instructions with supersession chains; and a dedicated Old → New Section Mapping page providing the concordance at a glance.
The resource is non-commercial, requires no login, and is intended purely as a working reference for fellow professionals. Feedback and correction suggestions are actively welcomed at support@taxbits.in - every flagged inconsistency makes the resource more reliable for the next user.
Closing Thoughts
The transition from the 1961 Act to the 2025 Act will, in retrospect, be remembered as one of the largest legislative changes in the working life of our profession. It is not a change of substance so much as a change of vocabulary - but vocabulary, for lawyers and accountants, is not a small thing. Every reference we make to "Section 143(3)" or "Section 68" for the next decade will require a quiet, internal act of translation.
The sooner each of us builds that translation reflex, the smoother the next few assessment years will be. I hope the resource referenced above proves useful in that effort.
The author, CA Abhay Anant Shastri, FCA (ICAI M.No. BB 037158) is Senior Partner at M/s SSAM & Co., Chartered Accountants (FRN 128097W), Pune, with offices in Pune, Bhosari, Nagpur, and Mumbai. He is also Founder & CEO of TaxBit Solutions Private Limited, the company behind TaxAppealSolutions - India's first AI-powered tax appeal automation platform. He has over four decades of experience in direct tax and GST litigation and serves as a Director on the board of a Cooperative Bank in Maharashtra.
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