Complete Guide to Computing Income Tax Under Income-tax Act 1961

Computation of income tax under the Income-tax Act 1961 essentially means working out the assessee’s total income, applying the correct tax rates and then adjusting for rebates, surcharge, cess and prepaid taxes to arrive at the final tax payable or refund. This guide recasts the FAQs into an easy-to-follow structure while retaining all statutory references and core concepts.

Important: All references to sections, rules, and case law in this write‑up are to be read exactly as per the Income-tax Act 1961 and related provisions. Only the explanatory text around them has been rephrased.

1. Timing and Modes of Payment of Income Tax

1.1 When is income tax actually paid?

Under the scheme of the Income-tax Act 1961, the exact tax liability on income for a particular year can be finally determined only once the previous year ends. However, for efficient and continuous collection of revenue, the law incorporates the “Pay as you earn” mechanism.

Accordingly, tax is usually paid during the year of earning income, not just after it ends. This advance collection happens through:

1. Voluntary payments made by the assessee into notified banks, such as:
   • Advance tax
   • Self-assessment tax
2. Tax Deducted at Source (TDS)
3. Tax Collected at Source (TCS)
4. Equalisation Levy (on specified digital transactions)

At the end of the year, these payments are adjusted against the final tax liability to determine tax payable or refund.

2. Heads of Income and Concept of Gross Total Income

2.1 How is income classified under the Act?

Section 14 of the Income-tax Act 1961 divides the income of an assessee into the following five heads:

• Salaries
• Income from house property
• Profits and gains of business or profession
• Capital gains
• Income from other sources

Every item of income has to be placed under the appropriate head and computed as per the specific provisions applicable to that head.

2.2 What is Gross Total Income (GTI)?

Once income under each of the five heads is determined (after allowing permissible expenses, exemptions, and set‑off of eligible losses), all these head-wise incomes are aggregated.

This aggregate is known as the Gross Total Income (GTI).

In short: GTI = Sum of income under all five heads (after intra-head and inter-head set-offs and adjustments permitted by law).

3. Difference Between Gross Total Income and Total Income

3.1 What is Total Income and how does it differ from GTI?

Total Income (often called taxable income) is the figure on which the tax rates are applied. It is derived by reducing the eligible deductions under Chapter VI‑A from the Gross Total Income.

• Deductions are available under Section 80C to Section 80U of Chapter VI‑A.
• These include, for example, specified investments (Section 80C), certain interest payments, medical insurance premiums, contributions to pension schemes, and others, subject to conditions.

Formula:
GTI – Deductions under Section 80C to Section 80U = Total Income

3.2 Illustrative computation framework

Below is a generic structure to understand the flow from GTI to Total Income:

Computation of Gross Total Income and Total (Taxable) Income

Note:

• While arriving at GTI, one has to adjust inter-source losses, inter-head losses, carried forward losses, unabsorbed depreciation, etc. as permitted under the Act.
• If an eligible assessee opts for the concessional tax regimes under section 115BAA, 115BAB, 115BAC, 115BAD or 115BAE, certain specified exemptions/deductions are not allowed while computing total income. The computation then follows the special rules of those sections.

4. Rounding Off Total Income – Section 288A

4.1 How should total income be rounded before tax calculation?

Section 288A requires that Total Income (after full computation as per the Act) must be rounded off to the nearest multiple of ten rupees.

Key rules:

1. Ignore any paise portion first.
2. After ignoring paise, look at the last digit of the rupee amount:
   • If the last digit is 5 or more, increase the amount to the next higher multiple of ten.
   • If the last digit is less than 5, reduce it to the next lower multiple of ten.
3. The rounded figure is treated as the assessee’s total income for all purposes.

4.2 Example

If the taxable income of Mr. Sharma is Rs. 2,52,944.99:

• Ignore 0.99 → amount = Rs. 2,52,944
• Last digit = 4 (< 5), so round down to Rs. 2,52,940.

If the total income is Rs. 2,52,945 or Rs. 2,52,946.30:

• Ignore paise in the second case → Rs. 2,52,946
• Last digit is 5 or 6 (≥ 5), so round up to Rs. 2,52,950.

5. Allowability of Personal and Charitable Expenditure

5.1 Can personal or household expenses be claimed as deduction?

No. Personal and household expenses are not deductible while computing taxable income under any head. Only those expenditures that are specifically allowed by the Income-tax Act 1961 under the relevant head of income can be claimed.

5.2 What if most of my income is donated to charity?

The use of income after it is earned does not generally alter the taxability of that income.