Sections 80AB and 80AC of the Income Tax Act 1961

How eligible income was computed for Chapter VI-A deductions and why timely filing of the income-tax return was mandatory for deductions in respect of certain incomes.

Updated: 28 September 2026

Current-law note: The Income-tax Act, 2025 came into force on 1 April 2026 and repealed the Income-tax Act, 1961, subject to transitional provisions. Sections 80AB and 80AC therefore remain important for tax years and proceedings governed by the 1961 Act. For the Income-tax Act, 2025, the corresponding general rules are consolidated principally in section 122, including section 122(5) on timely return filing and section 122(9) on computation of income for Part C deductions.

Sections 80AB and 80AC formed part of Chapter VI-A of the Income-tax Act, 1961. They did not create a separate deduction by themselves. Instead, they laid down conditions for calculating and claiming deductions available under the provisions dealing with deductions in respect of certain incomes.

In simple terms:

Section 80AB restricted the deduction to the qualifying income actually computed under the Income-tax Act and included in the assessee's gross total income.
Section 80AC required the return of income to be furnished on or before the due date under section 139(1) where the specified Chapter VI-A deduction was claimed.

Section 80AB: Deduction with reference to income included in gross total income

Section 80AB applied where a deduction was required to be made or allowed under a provision falling under the heading "C - Deductions in respect of certain incomes" in Chapter VI-A and the relevant nature of income was included in the assessee's gross total income.

Effect of Section 80AB: for computing the deduction, the relevant amount is the income of that nature computed in accordance with the provisions of the Act, before making a Chapter VI-A deduction. That computed amount is treated as the income derived or received by the assessee and included in gross total income.

What did Section 80AB mean in practice?

The section linked the quantum of a deduction to the amount of eligible income that formed part of gross total income after computation under the Act. A deduction could not ordinarily be calculated merely by taking a gross receipt or another figure without applying the statutory computation provisions that determine the relevant income.

Illustration: If a deduction provision applied to profits from an eligible activity, Section 80AB required the qualifying amount to be considered with reference to the income from that activity as computed under the Act and included in gross total income, rather than automatically treating the gross receipts from that activity as the deductible amount.

Section 80AC: Deduction not allowed unless return furnished by due date

Section 80AC imposed a return-filing condition for specified deductions. For assessment years beginning from 1 April 2006 but before 1 April 2018, it applied to deductions under sections 80-IA, 80-IAB, 80-IB, 80-IC, 80-ID and 80-IE. From assessment year 2018-19, its scope covered deductions under the provisions of Chapter VI-A falling under the heading "C - Deductions in respect of certain incomes".

Core condition: the relevant deduction was not allowable unless the assessee furnished the return of income for the assessment year on or before the due date specified in section 139(1) of the Income-tax Act, 1961.

What was the due date under Section 139(1)?

Section 139(1) prescribed the statutory due date for furnishing the return of income. The applicable date depended on the category of taxpayer and the circumstances specified in that provision, and could also be affected by a valid extension issued by the Central Board of Direct Taxes. Accordingly, the correct due date should be checked for the relevant assessment year rather than assumed from a general filing date.

How Sections 80AB and 80AC worked together

Provision	Main function under the 1961 Act	Practical question
Section 80AB	Determined the income base with reference to which a qualifying deduction was computed.	What amount of eligible income can be considered for the deduction?
Section 80AC	Made timely furnishing of the return a condition for specified deductions.	Was the return furnished within the statutory due date?

Thus, a taxpayer claiming an eligible deduction had to consider both the correct statutory computation of the qualifying income and the procedural condition relating to timely filing, where Section 80AC applied.

Current position under the Income-tax Act 2025

The Income-tax Act, 2025 came into force on 1 April 2026. The 1961 Act stands repealed from that date, but the transitional provisions preserve its application to earlier tax years and relevant proceedings. This means a page dealing with Sections 80AB and 80AC remains useful for matters governed by the repealed Act, but current transactions and tax years must be read under the 2025 Act.

Under the Income-tax Act, 2025, the general Chapter VIII rules are consolidated in section 122. In particular:

Section 122(5) provides that a deduction under Part C of Chapter VIII is not allowed where the assessee fails to furnish the return on or before the due date specified under section 263(1), or fails to make the deduction claim in a return furnished under section 263(1).
Section 122(9) substantially carries forward the computation principle formerly reflected in Section 80AB: the relevant income for a Part C deduction is the amount computed under the Act, before deductions under that Chapter, and included in gross total income.
Section 122(10) defines "gross total income" for Chapter VIII as total income computed under the Act before making deductions under that Chapter.

Old law and current law at a glance

Subject	Income-tax Act 1961	Income-tax Act 2025
Computation base for deductions in respect of certain incomes	Section 80AB	Section 122(9)
Timely return condition for relevant deductions	Section 80AC read with Section 139(1)	Section 122(5) read with Section 263(1)
Gross total income definition for the deduction chapter	Section 80B(5)	Section 122(10)

Key takeaways

Sections 80AB and 80AC were conditions governing Chapter VI-A deductions; they were not independent deductions.
Section 80AB focused on the amount of qualifying income actually computed under the 1961 Act and included in gross total income.
Section 80AC made timely return filing essential for the deductions to which it applied.
From 1 April 2026, current law is governed by the Income-tax Act, 2025, while the 1961 Act continues to matter for earlier tax years and proceedings under the statutory transition rules.

Official references

For the authoritative statutory text and current transition guidance, refer to the Income Tax Department:

Disclaimer: This article is for general legal and tax information. Applicability can depend on the tax year, deduction claimed, return-filing date, transitional provisions and facts of the case.