Income Tax Act 1961 vs 2025: Key Changes That Affect Your ITR Filing

If you filed your income tax return last year under the familiar Section 80C or Section 139 provisions, you might be wondering whether any of that changes now that a new Act has arrived. The Income Tax Act, 2025, which replaced the six-decade-old Income Tax Act, 1961, came into force on 1 April 2026 - and the transition is already underway.

This guide explains what has changed between the two Acts, which law governs your current ITR filing, how the Tax Year concept works, what happens to your existing deductions, and what every taxpayer - salaried or self-employed - needs to know before filing their next return.

What Is the Income Tax Act 2025 and Why Does It Replace the 1961 Act?

The Income Tax Act, 2025 is the new charging statute for direct taxes in India, enacted to replace the Income Tax Act, 1961, with effect from 1 April 2026. It contains 536 sections across 23 chapters and 16 schedules.

The 1961 Act had accumulated over 4,000 amendments across 65 Finance Acts and 19 standalone amendment bills. Provisos, explanations, and cross-references made everyday compliance difficult for taxpayers without professional assistance. The 2025 Act reorganises the same tax policy in a clearer, more logical structure - without changing the underlying tax burden.

For individuals and businesses seeking professional assistance with their annual filings, understanding this transition is essential. Explore income tax return filing services to ensure your compliance is handled correctly during this changeover period.

Key Terms You Should Know

• Tax Year (Section 3, ITA 2025): A 12-month period from 1 April to 31 March during which income is earned and assessed. It replaces the twin concepts of Previous Year and Assessment Year used under the 1961 Act.
• Previous Year (Section 3, ITA 1961): The financial year in which income is earned. Under the old Act, returns were filed in the following Assessment Year. This term no longer applies from Tax Year 2026-27.
• Assessment Year (ITA 1961): The year following the Previous Year in which income tax returns were filed and assessed. This concept has been discontinued under the 2025 Act.
• Succeeding Tax Year (ITA 2025): Replaces the concept of Assessment Year. Refers to the Tax Year immediately following the one in which income is earned - used for filing deadlines and assessment timelines.
• Section 536 (Repeal and Savings): The transition clause in the 2025 Act that ensures all pending proceedings, assessments, appeals, and refunds under the old Act continue to be governed by the 1961 Act for periods before 1 April 2026.
• Form 26 (ITA 2025): The unified audit report form replacing the earlier Forms 3CA, 3CB, and 3CD under the 1961 Act. Applicable from Tax Year 2026-27 onwards under Section 63 of the new Act.
• Form 121 (ITA 2025): A single merged declaration form replacing Form 15G and Form 15H. All eligible residents can use Form 121 to declare that estimated income is below the taxable limit, preventing unnecessary TDS deduction.

Who Needs to Understand the Income Tax Act 2025 Changes?

The transition from the 1961 Act to the 2025 Act affects every person liable to pay income tax in India. However, the level of impact varies by taxpayer category.

• Salaried individuals filing ITR-1 or ITR-2 - the filing process, standard deduction, and regime selection remain largely the same, but form naming conventions and section references change from Tax Year 2026-27
• Self-employed professionals and freelancers filing ITR-3 or ITR-4 - benefit from extended ITR filing due date of 31 August (previously 31 July for non-audit cases)
• Businesses requiring tax audit under Section 63 (earlier Section 44AB) - must transition to the unified Form 26 for audit reports
• HUFs, firms, and companies - must map old section references to new numbering for all compliance documents
• Senior citizens - benefit from increased TDS threshold on interest income (Rs 1 lakh) and merged Form 121 replacing Forms 15G and 15H
• Non-profit organisations and charitable trusts registered under Section 12A/80G - must comply with restructured Chapter XVI provisions and new Form 112 for audit reporting

If your business or personal finances involve multiple income heads, professional tax planning services can help you navigate the renumbered provisions and optimise your tax position under the new framework.

Legal Framework: Income Tax Act 1961 vs Income Tax Act 2025

The table below compares the key structural and procedural elements of the old and new Acts.

Note: The 1961 Act stands repealed from 01 April 2026 but continues to govern all proceedings, assessments, and appeals relating to tax years before that date under the Section 536 savings clause.

How to Transition Your ITR Filing: Step-by-Step Process

1. Identify Your Governing Law. If you are filing a return for income earned during FY 2025-26 (AY 2026-27), the Income Tax Act, 1961 governs your filing. The 2025 Act applies only for income earned from 1 April 2026 onwards. Do not confuse the date of filing with the governing law - even if you file in July 2026, the old Act applies for FY 2025-26 income.
2. Choose Your Tax Regime. The new tax regime under Section 115BAC (1961 Act) / Section 202 (2025 Act) remains the default. If you wish to opt for the old regime and have business income, file Form 10-IEA before the ITR due date. For non-business income, the regime choice can be made directly in the ITR form.
3. Map Your Deductions to Current Sections. For FY 2025-26 filing, continue using Sections 80C, 80D, 80E, etc., under the 1961 Act. From Tax Year 2026-27 filing, use the renumbered Sections 122-154 under the 2025 Act. The Income Tax Department provides a section mapping utility on incometaxindia.gov.in to cross-reference old and new sections.
4. Select the Correct ITR Form. CBDT has notified ITR-1 through ITR-7 for AY 2026-27. Key changes include: ITR-1 and ITR-4 now allow reporting of two house properties (up from one) and LTCG under Section 112A up to Rs 1.25 lakh. Ensure you are using the latest Excel utility or the e-filing portal for the correct AY.
5. Update Professional Compliance Documents. Businesses subject to tax audit services must transition to Form 26 for Tax Year 2026-27 audits. The earlier Form 3CA/3CB/3CD will no longer be applicable for periods starting 1 April 2026. Ensure your CA is aware of the new form requirements.
6. File Before the Due Date. For FY 2025-26 (AY 2026-27): ITR-1 and ITR-2 due by 31 July 2026. ITR-3 and ITR-4 (non-audit cases) due by 31 August 2026 (extended from 31 July). Audit cases due by 31 October 2026. Revised returns can be filed until 31 March 2027.
7. Verify and E-Verify Your Return. After filing, e-verify within 30 days using Aadhaar OTP, net banking, or bank account EVC. An unverified return is treated as not filed. The same verification process applies under both the old and new Acts.

Documents and Records Needed for Filing Under the New Framework

• Form 16 / Form 16A (renamed Form 130 under IT Rules, 2026 for Tax Year 2026-27 onwards) - TDS certificate from employer
• Form 26AS (continues for FY 2025-26 filing) / Form 168 (replaces Form 26AS from Tax Year 2026-27 - integrates Annual Information Statement data)
• Annual Information Statement (AIS) - cross-verify all financial transactions reported to the department
• PAN card and Aadhaar card - mandatory linkage continues under both Acts
• Bank statements for all accounts held during the year - for interest income, cash deposit verification
• Investment proofs for deductions under Sections 80C-80U (old Act) / Sections 122-154 (new Act) - PPF, ELSS, insurance premium receipts, NPS statements
• Home loan interest certificate under Section 24(b) - if claiming housing interest deduction
• Rent receipts and landlord PAN (if rent exceeds Rs 1 lakh per annum) for HRA exemption under Section 10(13A)
• Capital gains statements from broker/depository - for shares, mutual funds, property transactions
• Form 10-IEA (if opting for old tax regime with business income) - must be filed before ITR due date
• Form 26 (unified audit report) - for businesses requiring tax audit from Tax Year 2026-27
• Form 121 (merged 15G/15H declaration) - for eligible residents declaring income below taxable limit to prevent TDS

Income Tax Act 2025: Tax Slabs and Exemption Thresholds

The tax slabs under the 2025 Act remain identical to those introduced in Budget 2025. The new regime continues as the default option under Section 202 of the 2025 Act.

New Tax Regime Slabs (Default - FY 2025-26 / Tax Year 2026-27):

Note: Under Section 87A, the rebate of Rs 60,000 makes taxable income up to Rs 12 lakh effectively tax-free under the new regime. For salaried individuals, the standard deduction of Rs 75,000 means income up to Rs 12,75,000 is effectively tax-free. These thresholds are unchanged between the 1961 and 2025 Acts for FY 2025-26 and Tax Year 2026-27.

Common Mistakes to Avoid During the Transition

Mistake 1: Assuming the 2025 Act applies to FY 2025-26 filing. The most common error is believing that because the new Act commenced on 1 April 2026, your ITR filing this year falls under it. It does not. Your FY 2025-26 return filed in July/August 2026 is still governed entirely by the Income Tax Act, 1961. If you have received an income tax notice for a prior year, it will continue under the old Act.

Mistake 2: Citing new section numbers for old-year returns. If you are filing for FY 2025-26 or any prior year, all section references in your ITR, audit reports, and correspondence must use the 1961 Act numbering. Using 2025 Act sections for a pre-April 2026 period will create processing errors and potential defect notices.

Mistake 3: Believing that deductions under 80C/80D have been removed. The 2025 Act retains all existing deductions - they have simply been renumbered under Sections 122-154 and reorganised into schedules. The Rs 1.5 lakh limit under Section 80C (old) continues under the corresponding new provision. No deduction has been withdrawn.

Mistake 4: Ignoring the extended due date for ITR-3 and ITR-4. Self-employed professionals and businesses not requiring tax audit now have until 31 August 2026 (extended from 31 July). Missing this revised deadline means late filing fees under Section 234F apply. Mark the new date in your compliance calendar.

Mistake 5: Not updating tax software or templates to the 2025 Act for Tax Year 2026-27. From income earned starting 1 April 2026, your accounting software, payroll systems, and compliance templates must reference the new Act and Rules 2026. Continuing to use old section numbers in invoices, challans, or TDS certificates will cause mismatches during processing.

Penalties for Non-Compliance Under the New Act

The penalty framework under the Income Tax Act, 2025 largely mirrors the 1961 Act, with some clarifications and additions.

Under Section 300 of the Income Tax Act, 2025, misreporting of income continues to attract a penalty of 200% of the tax payable on the misreported amount. This provision now includes explicitly defined bright-line tests for what constitutes misreporting - a clearer standard than the 1961 Act provided.

A new penalty has been introduced for failure to comply with notices issued under faceless assessment. The penalty ranges from Rs 10,000 to Rs 1,00,000, depending on the nature and frequency of non-compliance. This is aimed at ensuring taxpayers engage meaningfully with the digital assessment process.

Under the old Act, failure to file ITR by the due date attracted a late fee of Rs 5,000 under Section 234F (reduced to Rs 1,000 if total income was below Rs 5 lakh). This provision continues under the 2025 Act in corresponding sections, with no change to the amounts.

Additionally, interest under Section 234A (interest for delay in filing), Section 234B (interest for default in advance tax), and Section 234C (interest for deferment of advance tax) continue at 1% per month under corresponding provisions of the new Act.

How the Income Tax Act 2025 Connects with Other Provisions

The 2025 Act operates within a broader compliance ecosystem. The TDS framework under Section 393 of the new Act consolidates all deduction-at-source provisions that were previously scattered across Sections 192 to 206C of the 1961 Act. This means that businesses handling TDS return filing must now reference a single consolidated section instead of navigating multiple provisions for salary TDS, interest TDS, rent TDS, and professional fee TDS.

The transition clause under Section 536 creates a dual-track system where both Acts coexist. Any search, assessment, reassessment, penalty, or appeal initiated before 1 April 2026 continues under the 1961 Act. A search initiated on or after that date follows the new block-assessment machinery under the 2025 Act. This means the Income Tax Appellate Tribunal (ITAT), High Courts, and the Supreme Court will simultaneously adjudicate matters under both statutes for several years.

The new Income Tax Rules, 2026, which replaced the Income Tax Rules, 1962, are an integral companion to the 2025 Act. Changes in the Rules include increased children education allowance exemption from Rs 100 per month to Rs 3,000 per month, HRA calculation including 50% of basic pay for Bangalore, Pune, Hyderabad, and Ahmedabad, and modified PAN quoting requirements for high-value transactions.

What Does the Income Tax Act 2025 Cover? Key Structural Changes

Key Takeaways

The Income Tax Act, 2025 replaced the Income Tax Act, 1961 with effect from 1 April 2026, reducing the statute from 819 sections to 536 sections while retaining the same tax rates, slabs, and deduction limits.

For FY 2025-26 (AY 2026-27), taxpayers must continue filing under the Income Tax Act, 1961 - the new Act governs only income earned from 1 April 2026 onwards.

The "Tax Year" concept under Section 3 of the 2025 Act replaces the dual Previous Year and Assessment Year terminology, eliminating one of the most common sources of confusion for taxpayers.

Section 536 of the new Act creates a dual-track system where both Acts coexist - all pending proceedings for pre-April 2026 periods continue under the old law, while new periods are governed by the 2025 Act.

No deduction or exemption has been withdrawn - all provisions under Sections 80C to 80U of the 1961 Act are retained under renumbered Sections 122 to 154 of the 2025 Act, and the Rs 12 lakh effective tax-free threshold under the new regime continues unchanged.

Need Help with Income Tax Return Filing?

Navigating the transition between two income tax Acts requires understanding which law applies to your specific filing, mapping old deduction sections to new numbers, and ensuring your compliance documents reference the correct provisions. Whether you are filing for FY 2025-26 under the 1961 Act or preparing for Tax Year 2026-27 under the new framework, professional guidance can save time and prevent costly errors.

Explore our income tax return filing services for end-to-end compliance support during this transition.

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