Chapter I - Preliminary
Section 1
Section 1: short title, extent and commencement
Section 1 is the opening section of the Income-tax Act, 2025. It does three simple things - it gives the Act its official name, states that it applies across the whole of India, and fixes the date from which the Act takes effect.
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Need advice on Section 1?
This article is for general information. Refer to the Income-tax Act, 2025 as amended by the Finance Act, 2026 and the Taxation and Other Laws (Amendment) Act, 2026 for the official provisions. If you need professional advice for your situation, contact Bizeneed.
Statutory text
Bare law
(1) This Act may be called the Income-tax Act, 2025.
(2) It extends to the whole of India.
(3) Save as otherwise provided in this Act, it shall come into force on the 1st April, 2026.
Introduction
Section 1 names the Income-tax Act, 2025, extends it across India and sets 1 April 2026 as its commencement except where the Act itself provides otherwise. For a particular transaction or deduction, check its specific effective-date clause too.
Key takeaways
Official name
The law is called the Income-tax Act, 2025.
Territorial reach
Section 1 extends the Act to the whole of India.
Commencement
The general start date is 1 April 2026, unless another provision of the Act specifies otherwise.
What Section 1 says
"(1) This Act may be called the Income-tax Act, 2025."
"(2) It extends to the whole of India."
"(3) Save as otherwise provided in this Act, it shall come into force on the 1st April, 2026."
What this means in practice
The Act's short title is the "Income-tax Act, 2025" - this is the citation used to refer to the law, replacing the earlier Income-tax Act, 1961.
It has territorial application across the whole of India, without any regional carve-out in this section.
The default commencement date is 1 April 2026, except where the Act itself specifies a different date for a particular provision ("save as otherwise provided in this Act").
Practical scope
The date in the short title and the commencement date answer different questions. “2025” identifies the Act; subsection (3) generally brings it into force on 1 April 2026, subject to what the Act provides otherwise.
For a business using an old checklist or contract reference, identify the actual legal provision instead of changing the year in its citation alone. Renumbering, changed wording and transitional rules require a provision-specific comparison.
Limits and separate checks
Territorial extent does not by itself determine whether a particular receipt is taxable or whether a person is resident. Those issues depend on the charging, scope and residence provisions.
A document issued after commencement can concern an earlier period. The issue date alone does not establish that every substantive or procedural question is governed by the new Act; examine the applicable saving and transitional provisions.
Step-by-step applicability review
1. Identify the income period, transaction date and proceeding involved.
2. Use the official short title to identify which Act the document cites.
3. Check the general commencement rule and any specific effective-date or transitional provision relevant to the issue.
4. Record the legal basis used for the particular obligation before updating a filing or compliance checklist.
Records and checklist
The income period and dates of the transaction or proceeding.
The exact Act and provision cited in each document.
Any specific commencement, saving or transition provision applicable to the issue.
Official amended Act source
Step-by-step flow for applying Section 1
- 1
Which law does the document or issue refer to?
Section 1(1) gives the short title: the Income-tax Act, 2025. Note the exact Act and provision cited.
- 2
Is the place or person within the territorial extent?
Section 1(2) extends the Act to the whole of India. Extent alone does not decide whether an amount is taxable or whether a person is resident.
- 3
Does the issue relate to a period or event from 1 April 2026 onwards?
Section 1(3) sets 1 April 2026 as the general commencement date.
- Yes, and no special provision applies: The Act applies from its general commencement date.
- No, or the facts straddle the date: Go to the next step.
- 4
Does the Act provide otherwise for this provision?
The words "save as otherwise provided in this Act" mean a specific commencement, saving or transitional provision prevails over the general date. Check it before deciding which regime governs.
Practical checklist
Do
- Identify the tax year and the provision's own commencement or transitional rule.
- For pre-2026 facts, check the Act's savings and transition provisions before choosing a legal regime.
Avoid
- Do not assume every provision takes effect on a date different from the Section 1 default without express text.
- Do not treat the Act's title or territorial reach as a tax calculation rule.
Illustrative example
Worked example: a contract clause citing the old Act
Hypothetical facts (illustration only, not a real taxpayer): A trading firm reviews a supply contract signed in 2025 whose tax clause refers to the Income-tax Act, 1961. In May 2026 it wants to update its compliance checklist for a payment made in that month.
Identify the Act
Under Section 1(1), the current law is cited as the Income-tax Act, 2025. The contract's reference to the 1961 Act does not change which Act is in force.
Check commencement
The payment is made in May 2026, after the general commencement date of 1 April 2026 under Section 1(3).
Check for a different rule
Because Section 1(3) is subject to "save as otherwise provided in this Act", the firm checks whether a specific provision or transitional rule applies to this type of payment before relying only on the general date.
Map the provision
The firm identifies the corresponding provision in the 2025 Act on its own wording rather than simply replacing the year in the old citation.
Outcome
- For the May 2026 payment the general rule points to the Income-tax Act, 2025, subject to any provision-specific exception.
- Section 1 settles which Act applies and from when; whether and how the payment is taxed depends on the substantive provisions.
Glossary
- Commencement
- The date from which the Act operates, subject to express exceptions.
- Extent
- The territory to which the Act applies: the whole of India.
Frequently asked questions
When does the Income-tax Act, 2025 come into force?
As a general rule, on 1 April 2026, except where the Act itself provides a different commencement date for a specific provision.
Does the Act apply to the whole of India?
Yes - Section 1(2) extends the Act to the whole of India.
Does the year 2025 in the title mean the Act generally commenced in 2025?
No. The title identifies the law; Section 1(3) states the general commencement date of 1 April 2026.
Does a notice dated after commencement automatically settle which law applies?
No. Check the period and the relevant saving, transition and substantive provisions.
Need help applying this provision to your situation?
Talk to our tax team about this sectionLast updated 10 October 2026