Income Tax Act, 2025: Old Sections vs New Sections Mapping Guide

If you’ve filed taxes in India before, you probably know a few section numbers by heart: 80C for tax-saving investments, 24(b) for home loan interest, 194J for professional fees TDS. From 1 April 2026, all of that muscle memory needs an update.

The Income-tax Act, 2025 has replaced the Income-tax Act, 1961, and while the tax rules themselves haven’t changed much, almost every section number has. This guide breaks down exactly what moved where, why the change happened, and what you actually need to remember, in plain language, without the legal jargon.

Why Was the Income Tax Act Renumbered?

The old Income-tax Act, 1961 was amended thousands of times over more than six decades. Sections got squeezed in with letters and decimals (think 80CCD(1B), 194-IA, 115BAC) until the structure became genuinely hard to navigate. A single provision often needed you to jump across five cross-referenced sections just to understand one rule.

The Income Tax Act 2025 was built to fix exactly that. It consolidates roughly 819 sections and 5,500+ sub-sections of the old Act into about 536 simpler, sequentially numbered sections across 23 chapters, grouping related provisions (like all TDS rules) under a single chapter instead of scattering them everywhere.

Importantly, this is a structural and drafting reform, not a tax reform. Tax slabs, deduction limits, and rebate amounts continue exactly as notified under the Finance Act. Only the section numbers and, in places, the language have changed.

When Does the New Act Apply?

This is the part that trips people up the most, so let’s be precise:

• The Income Tax Act, 2025 is effective from 1 April 2026.
• Your ITR for FY 2025-26 (AY 2026-27), filed in July 2026, still uses the old 1961 Act and its old section numbers.
• The new section numbers apply from Tax Year 2026-27 onwards, i.e., returns you’ll file in July 2027.
• Any pending assessments, appeals, or notices relating to periods before 1 April 2026 continue to be governed by the 1961 Act. The new Act does not apply retrospectively.

So if you’re filing this July, don’t panic: nothing changes for you just yet. But it’s smart to get familiar with the new numbers now, since payroll systems, Form 16, and accounting software are already being updated in the background.

Another Big Change: “Tax Year” Replaces “Previous Year” and “Assessment Year”

For decades, Indian taxpayers had to juggle two overlapping concepts:

• Previous Year (FY): the year in which income is earned
• Assessment Year (AY): the following year in which that income is taxed

The 2025 Act scraps this two-step system entirely and introduces a single, simpler idea: the Tax Year, a 12-month period from 1 April to 31 March in which income is both earned and reported. No more explaining to confused clients why “AY 2026-27” refers to income earned in “FY 2025-26.”

Complete Old vs New Section Mapping Table

Here’s a ready-reference table of the most commonly used sections, mapped from the 1961 Act to the 2025 Act.

Note: Section numbering for some less common or highly specific provisions may vary slightly across different professional mapping tools until the final CBDT concordance table is universally referenced. Always cross-check less-common provisions against the official mapping utility before quoting them in a legal filing, contract, or opinion.

The Big TDS Consolidation: Sections 392, 393 & 394

If there’s one change every business owner, freelancer, and accountant should know cold, it’s this one.

Under the old Act, TDS provisions were scattered across dozens of separate sections: 192 for salary, 194C for contractors, 194J for professional fees, 194-IA for property purchases, and so on. The 2025 Act consolidates almost the entire TDS framework into just three sections:

• Section 392: TDS on salary payments (replaces old Section 192)
• Section 393: TDS on virtually every other type of payment: contractors, professional fees, rent, commission, e-commerce transactions, virtual digital assets, and more, distinguished using standardised payment/nature codes instead of separate section numbers
• Section 394: Tax Collected at Source, TCS (replaces old Section 206C)

The rates and thresholds haven’t changed: 1% TDS on contractor payments is still 1%, and professional fee TDS is still 10%. What’s changed is purely administrative: when filing TDS returns, generating certificates, or making challan payments, you now cite the new section plus a payment code, rather than a standalone old-style section number.

This matters practically because old TDS codes are being rejected by the CPC (Centralized Processing Cell) from Q1 FY 2026-27 onwards. If your accounting software or ERP system isn’t updated, deductees may not see their TDS credit reflected in Form 26AS, and you could face compliance notices.

What Hasn’t Changed (So You Don’t Over-Correct)

It’s just as important to know what’s stayed the same, so you don’t panic-update things that don’t need it:

• Tax slabs and rates: unchanged under both the old and new tax regimes
• Deduction limits: ₹1.5 lakh under 80C (now 123), ₹25,000/₹50,000 under 80D (now 126); all limits carried forward as-is
• PAN, TAN, and faceless assessment infrastructure: remain valid and unchanged
• Filing deadlines and due dates: the compliance calendar is the same
• Audit thresholds: tax audit obligations continue under their renumbered equivalent (Section 63)

New Forms to Know

Alongside the renumbered sections, the Income Tax Rules, 2026 introduce a few new forms worth noting:

• Form 168: new equivalent of Form 26AS
• Form 130: set to replace Form 16 for salary TDS certificates
• Form 121: merged successor to the old Form 15G and Form 15H (declarations for non-deduction of TDS)

Frequently Asked Questions (FAQs)

For further reading and detailed analysis, refer to this resource.