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Case lawIncome-tax Rules 2026 › Rule 146
Rules 2026s.227s.228s.231s.232

Rule 146 of the Income-tax Rules, 2026

Rule 146 — Rules related to application for exercising the option for tonnage tax scheme and other matters related to it. Made under s.227, s.228, s.231, s.232 of the Income-tax Act, 2025.

Where this rule sits

Rule 146 gives effect to Section 227, Section 228, Section 231 and Section 232 of the Income-tax Act, 2025. A rule cannot go beyond the section it serves: where the two seem to differ, the section governs.

← Rule 145  ·  Rule 147 →

What this rule does

The rule collects five matters for the Tonnage Tax Scheme under Chapter XIII-G.

Clause (a) prescribes Form No. 80 for an application under section 231(1) to opt for the Tonnage Tax Scheme and for an application under section 231(10) to renew the option, to be verified as specified in the form.

Clause (b) prescribes how deemed tonnage under section 227(4)(b) is computed for two arrangements, by a Table: for the purchase of slots and slot charter, 2.5 teu equals 1 Net Tonnage, teu being a Twenty foot Equivalent Unit; and for the sharing of a break-bulk vessel, where cargo is restricted by volume, 19 cubic metres equals 1 net tonnage, and where cargo is restricted by weight, 14 metric tons equals 1 net tonnage.

Clause (c) lists the incidental activities referred to in section 228(7): maritime consultancy charges; income from loading or unloading of cargo; ship management fees or remuneration received for managed vessels; and maritime education or recruitment fees.

Clause (d) provides that the limit for charter-in of tonnage of qualifying ships referred to in section 232(15) to (20) during any tax year is computed by dividing the total number of chartered-in ton days by the total number of ton days operated by the company. Clause (e) prescribes Form No. 81 for the audit report of a qualified company required under section 232(21)(b).

Why it is there

The tonnage tax scheme taxes a shipping company on the tonnage of its ships rather than on its profits, so the Act has to be told how tonnage is counted where a company does not own the whole ship, and what counts as an incidental activity whose income stays inside the scheme. Section 227(4)(b), section 228(7) and section 232(15) to (20) each leave a piece of that to be prescribed. The rule supplies the conversion bases, the list of incidental activities and the formula for the charter-in limit, and prescribes the forms for opting in, renewing and reporting.

Who it applies to

The figures, and what each one turns on

Read the condition in the same row. A figure quoted without it is a wrong answer with a citation attached.
WhatFigureThe condition on itWhere
Deemed tonnage for purchase of slots and slot charter2.5 teu = 1 Net Tonnage (1 nt)Teu is a Twenty foot Equivalent Unit, that is, a container of that sizeClause (b), Table Sl. No. 1
Deemed tonnage for sharing of a break-bulk vessel where cargo is restricted by volume19 cubic metres = 1 net tonnage (1 nt)Applies only where the cargo is restricted by volumeClause (b), Table Sl. No. 2(i)
Deemed tonnage for sharing of a break-bulk vessel where cargo is restricted by weight14 metric tons = 1 net tonnage (1 nt)Applies only where the cargo is restricted by weightClause (b), Table Sl. No. 2(ii)
Charter-in limit computationTotal number of chartered-in ton days divided by the total number of ton days operated by the companyFor the limit referred to in section 232(15) to (20) during any tax year; the rule prescribes the method of computation, and the limit itself is in those sub-sectionsClause (d)

The forms it prescribes

What this means in practice

Clause (d) gives the method, not the limit: the proportion of chartered-in ton days to ton days operated is how the limit referred to in section 232(15) to (20) is measured, and the permitted proportion itself is in those sub-sections, not in the rule. The conversion bases in clause (b) are not interchangeable — for a break-bulk vessel it depends on whether the cargo is restricted by volume or by weight, and applying the volume basis to weight-restricted cargo changes the tonnage and therefore the tax. The list of incidental activities in clause (c) is a closed list for section 228(7). One form covers both opting in and renewal, so the same Form No. 80 is used at the start and at renewal under section 231(10).

An example

Illustrative only, and invented for this page. The figures are chosen to show the requirement biting, not taken from any real matter.

A shipping company purchases slot capacity equivalent to 5,000 teu during the tax year. Under entry 1 of the Table in clause (b), 2.5 teu equals 1 Net Tonnage, so the deemed tonnage is 2,000 nt. If it also shares a break-bulk vessel carrying weight-restricted cargo of 28,000 metric tons, entry 2(ii) converts that at 14 metric tons to 1 nt, giving a further 2,000 nt.

Where you meet this rule

In Form No. 80 when the option for the Tonnage Tax Scheme is exercised or renewed, in the tonnage computation for the year, and in the Form No. 81 audit report a qualified company furnishes under section 232(21)(b).

The words themselves

2.5 TEU = 1 Net Tonnage (1 NT), where TEU is Twenty foot Equivalent Unit (Container of this size).
Rule 146(b), Table Sl. No. 1, Income-tax Rules, 2026.
the limit for charter-in of tonnage of the qualifying ships referred to in section 232(15) to (20) during any tax year, shall be computed by dividing the total number of chartered-in ton days by the total number of ton days operated by the company
Rule 146(d), Income-tax Rules, 2026.

What people get wrong

What this page does not tell you. It does not reproduce the rule. Everything above was written from the rule’s own text as the Income Tax Department publishes it — the text is here. A rule is subordinate legislation: it prescribes the method, the form or the period, and it cannot enlarge the charge the section imposes. Where a figure matters, read the sub-rule it comes from.