If you have used the Income-tax Act, 1961 for years, the 2025 Act's renumbering is the single most disorienting part of the transition. Nothing you rely on has been taken away — but almost everything has moved. This is a quick reference for the sections people actually look up.
Two things to keep straight before you use it:
- The mapping does not change your tax. The 2025 Act is a re-codification: same rates, same deductions, cleaner drafting and new numbers.
- Which Act applies depends on the year the income was earned, not when you file. FY 2025-26 (AY 2026-27) is still the 1961 Act. From 1 April 2026 onwards, the 2025 Act. See our full comparison of the two Acts.
Basics and the tax year
| Provision | 1961 Act | 2025 Act |
|---|
| Scope of total income | s.5 | s.5 |
| Residential status | s.6 | s.6 |
| Income deemed to accrue in India | s.9 | s.9 |
| Previous year / Tax Year | s.3 | s.3 (now "Tax Year") |
| PAN / Aadhaar linkage | ss.139A / 139AA | s.262 |
Deductions, rebate and relief
| Provision | 1961 Act | 2025 Act |
|---|
| Chapter VI-A deductions block | ss.80C–80U | ss.122–154 |
| LIC / PF / ELSS deduction | s.80C | s.123 |
| Mediclaim | s.80D | s.126 |
| Inter-corporate dividend deduction | s.80M | s.148 |
| Rebate for resident individuals | s.87A | s.156 |
| Relief for salary arrears (Form 10E) | s.89 | s.157 |
Note the trap here: s.87A becomes s.156, and s.157 is the old s.89 (arrears relief) — two different reliefs sitting next to each other. Getting these two the wrong way round is an easy mistake.
Regimes and rates
| Provision | 1961 Act | 2025 Act |
|---|
| New (default) regime for individuals | s.115BAC | s.202 |
| Concessional corporate regime | s.115BAA | s.200 |
| New-manufacturing corporate regime | s.115BAB | s.201 |
| MAT | s.115JB | s.206 |
Capital gains
| Provision | 1961 Act | 2025 Act |
|---|
| Charge of capital gains | s.45 | s.67 |
| Mode of computation | s.48 | s.72 |
| Cost / improvement definitions | ss.55 / 55A | ss.90 / 91 |
| STCG on STT-paid listed equity | s.111A | s.196 |
| LTCG on STT-paid listed equity | s.112A | s.198 |
| Other LTCG | s.112 | s.197 |
| Exemption — house to house | s.54 | s.82 |
| Exemption — bonds | s.54EC | s.85 |
| Exemption — any asset to house | s.54F | s.86 |
| Shift from urban area / to SEZ | ss.54G / 54GA | ss.87 / 88 |
| Extension of time | s.54H | s.89 |
Business, presumptive and audit
| Provision | 1961 Act | 2025 Act |
|---|
| Depreciation | s.32 | s.33 |
| Actual-payment items | s.43B | s.37 |
| Cash-expenditure cap | s.40A(3) | s.36 |
| Presumptive taxation | ss.44AD / 44ADA / 44AE | s.58 |
| Books of account | s.44AA | s.62 |
| Tax audit | s.44AB | s.63 |
| Method of accounting / ICDS | ss.145 / 145A | ss.276 / 277 |
TDS and TCS
| Provision | 1961 Act | 2025 Act |
|---|
| Whole TDS framework (194 series etc.) | 40+ sections | consolidated, principally s.393 |
| Salary TDS | s.192 | s.392 |
| Contractors / professional / rent / goods | ss.194C / 194J / 194-I / 194Q | s.393(1) |
| Payments to non-residents | s.195 | s.393(2) |
| Lower-deduction certificate | s.197 | s.395 |
| Consequences of default | s.201 | s.398 |
Returns, assessment and appeals
| Provision | 1961 Act | 2025 Act |
|---|
| Return of income (all types) | s.139 | s.263 |
| Self-assessment | s.140A | s.266 |
| Intimation | s.143(1) | s.270(1) |
| Scrutiny selection | s.143(2) | s.270(10) |
| Reassessment | ss.147–148 | ss.279–281 |
| Limitation for reassessment | s.149 | s.282 |
| Sanction for notice | s.151 | s.284 |
| Rectification | s.154 | s.287 |
| Notice of demand | s.156 | s.289 |
| Interest (234A/B/C) | ss.234A–234C | ss.423–425 |
| Under-reporting penalty | s.270A | s.439 |
| Penalty immunity application | s.270AA | s.440 |
| Appeal to CIT(A) | s.249 | s.358 |
| Appeal to ITAT | s.253 | s.362 |
International and treaty
| Provision | 1961 Act | 2025 Act |
|---|
| DTAA relief | s.90 | s.159 |
| NRI concessional chapter | ss.115C–115I | ss.212–218 |
| Transfer pricing | ss.92–92F | ss.161–173 |
| Thin capitalisation | s.94B | s.177 |
How to use this
For a past year (AY 2026-27 and earlier), keep citing the 1961 numbers — that is correct, not outdated. From Tax Year 2026-27 onwards, notices, TDS certificates and software codes will carry the new numbers. If a document about an old year quotes an old section, it is right; if a document about 2026-27 onwards still quotes old numbers, it needs updating.
This is a working reference, not the statute. For anything you are filing or relying on, confirm the section text against the Act or the department's official 1961-vs-2025 comparison utility.