U.S. · Tax forms
Form 1120 line 30, taxable income.
How taxable income is figured on Form 1120 and how it drives the tax computation.
Line 30 (“Taxable income. Subtract line 29c from line 28”) is the figure the corporation’s tax is based on. Schedule J, line 1a multiplies page 1, line 30 by 21% (0.21).
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Result
How line 30 is built, 2025 form
| Line | Meaning | What the IRS says |
|---|---|---|
| Line 28 | Taxable income before NOL and special deductions | Subtract line 27 from line 11 |
| Line 29a | Net operating loss deduction | See instructions |
| Line 29b | Special deductions | Schedule C, line 24 |
| Line 29c | Add lines 29a and 29b | Subtracted from line 28 |
| Line 30 | Taxable income | Subtract line 29c from line 28 |
| Minimum taxable income | Floor on line 30 | Cannot be less than the largest of the inversion gain (section 7874(a)) and the REMIC excess inclusions amount |
| Zero or less | Possible NOL | If line 30 figured without the minimum amounts is zero or less, the corporation may have an NOL carried to other tax years |
| Capital construction fund | Reduce line 30 | Reduce the amount otherwise entered on line 30 by the deduction; enter “CCF” and the amount on the dotted line (section 7518) |
| Tax rate | Schedule J, line 1a | Multiply taxable income (page 1, line 30) by 21% (0.21) |
Minimum taxable income
The instructions say taxable income cannot be less than the largest of the inversion gain of the corporation for the tax year, if it is an expatriated entity or a partner in one (section 7874(a)), and the sum of the excess inclusions from its residual interest in a REMIC from Schedules Q (Form 1066), line 2c, and its FASIT-related taxable income.
Line 30 and the tax
Line 30 is the base for Schedule J, line 1a. The result flows through the Schedule J additions and credits to Schedule J, line 12 total tax, which is entered on page 1, line 31.
When line 30 is zero or less
The instructions say the corporation may have an NOL that can be carried as a deduction to other tax years. Carryback is limited to farming losses and insurance company losses (other than life insurers).
Worked example
Cedar Ridge Studios, Inc. (made up) shows $65,800 on line 28 and has no NOL or special deductions, so line 29c is $0 and line 30 is $65,800. Schedule J, line 1a is 0.21 × 65,800 = $13,818. Names and figures are made up.
More line pages in this set
Related lines: Form 1120 Line 11, Form 1120 Line 26, Form 1120 Line 28, Form 1120 Line 29a, Form 1120 Schedule J Line 12, Form 1120 Schedule J Line 17, Form 1120 Schedule J Line 18.
Sources
- Instructions for Form 1120 (2025): the line-by-line instructions on this page. Page last reviewed or updated April 30, 2026. Read November 2, 2026.
- Form 1120 (2025), U.S. Corporation Income Tax Return: the printed line wording and arithmetic on the form (Form 1120 (2025), created 9/26/25). Read November 2, 2026.
Tax year 2025 forms and instructions: Form 1120 (2025) and its 2025 instructions. Line numbers and labels were read from the IRS PDF and instructions on the date read and can change between tax years, so check them against the form for your year. Names in worked examples are made up.
Frequently asked questions
What is Form 1120 line 30?
Taxable income: line 28 minus line 29c, where line 29c adds the net operating loss deduction and the special deductions.
What tax rate applies to line 30?
The Schedule J instructions say to multiply taxable income (page 1, line 30) by 21% (0.21) and enter the result on Schedule J, line 1a.
Can taxable income be less than zero?
Line 30 can be zero or less before the minimum rules apply; the instructions then say the corporation may have an NOL available for other tax years.
What is minimum taxable income?
A floor: taxable income cannot be less than the largest of the inversion gain under section 7874(a) and the REMIC excess inclusions amount described in the instructions.
What is the CCF note beside line 30?
To deduct contributions to a capital construction fund, reduce line 30 by the deduction and enter “CCF” and the amount on the dotted line next to it (section 7518).
Not tax advice
This page summarizes IRS instructions, mostly written for the people who prepare the form, and is not tax, legal or financial advice. A CPA or an enrolled agent can confirm what a line means for your return. Everything runs in your browser; nothing you enter is sent anywhere.