13b — Additional Deductions Updated for tax year 2025

What this line means

Other deductions not included in the standard/itemized deduction on line 12e or the QBI deduction on line 13a. This line captures specific deductions that Congress has authorized separately, such as the net operating loss deduction or other deductions reported on Schedule 1. For most filers, this line is zero.

Does this apply to you?

• You have a net operating loss (NOL) carryforward from a prior year
• You have deductions from Schedule 1 that flow to this line
• You have specific deductions authorized by separate IRS provisions that do not fit on other lines
• You are claiming deductions related to income reported on Schedule 1

Easy to overlook

Net operating loss carryforwards from prior years If you had a business loss in a prior year that exceeded your other income, the unused loss carries forward as a net operating loss. This carryforward reduces your taxable income in future years and is reported on this line. Filers who had a bad business year in the past sometimes forget to carry the loss forward, losing the tax benefit permanently. ¹ [SOURCE: IRS Form 1040 instructions — Line 13b]

The above-the-line charitable deduction for non-itemizers has expired In 2020 and 2021, non-itemizers could deduct up to $300 ($600 for joint filers) in charitable contributions directly on the return. This provision expired after 2021. Filers who got used to this deduction sometimes still try to claim it here. For 2025, charitable contributions are only deductible if you itemize on Schedule A. ² [SOURCE: General filing pattern — charitable deduction for non-itemizers expired]

Watch out for this

Entering amounts on this line without proper documentation. Any deduction claimed on line 13b must be supported by a specific schedule or form. Entering an arbitrary amount without an attached form will trigger an IRS inquiry. If you are unsure whether a deduction belongs here, check the line 13b instructions for the specific list of qualifying deductions.

Related lines on your return

• Line 13a — Form 1040 — Qualified business income deduction; a separate deduction from 13b
• Line 14 — Form 1040 — Total deductions; the sum of lines 12e, 13a, and 13b
• Schedule 1 — Form 1040 — Where many of the deductions flowing to 13b originate