Line 24z on Schedule 1 of Form 1040 is a write-in catch-all for above-the-line adjustments to income that the tax code allows but the form doesn’t give a dedicated line. For the 2025 tax year, Lines 24a through 24k already cover eleven specifically named adjustments, so Line 24z captures only what’s left. In practice, most filers never need it.
Check First Whether Your Adjustment Has Its Own Line
Before writing anything on 24z, confirm your item isn’t already assigned a line. The IRS has been steadily breaking previously catch-all items out into their own numbered lines, and several deductions that used to land on 24z no longer do.
On the 2025 Schedule 1, these adjustments each have a dedicated line in the 24a–24k block:
- Line 24a: jury duty pay you turned over to your employer.
- Line 24b: expenses from renting personal property for profit when the rental isn’t a trade or business.
- Line 24c: the nontaxable value of Olympic or Paralympic medals and prize money from the U.S. Olympic Committee, for athletes with AGI at or below $1 million ($500,000 if married filing separately).
- Line 24d: reforestation amortization and expenses under IRC Section 194 for qualified timber property, amortized over 84 months (up to $10,000 a year, or $5,000 for married filing separately).
- Line 24e: repayment of supplemental unemployment benefits under the Trade Act of 1974.
- Line 24f: contributions to Section 501(c)(18)(D) pension plans.
- Line 24g: contributions by certain chaplains to Section 403(b) plans.
- Line 24h: attorney fees and court costs for unlawful discrimination claims.
- Line 24i: attorney fees and court costs connected to an IRS whistleblower award.
- Line 24j: housing deduction from Form 2555 (foreign earned income).
- Line 24k: excess deductions of Section 67(e) expenses from Schedule K-1 (Form 1041), passed through from estates and trusts.
A few other adjustments that get mistaken for 24z items sit higher up in Part II: educator expenses on Line 11, business expenses of reservists, qualified performing artists, and fee-basis government officials on Line 12, and the Archer MSA deduction on Line 23. If your deduction is any of these, use the dedicated line.
If you’re working from an older guide or last year’s return, verify against the current form before putting something on 24z. Items that correctly went there two or three years ago may now have their own line.
What Actually Belongs on Line 24z
After the named lines are accounted for, 24z holds any remaining adjustment to income the tax code authorizes but the form doesn’t name. These are edge cases.
One concrete example is the exclusion for energy conservation subsidies under IRC Section 136. When a public utility gives you a subsidy to install energy-efficient equipment at home, the subsidy is excluded from gross income. If the amount shows up on a tax information form you receive, you may need an offsetting adjustment on 24z to back it out of reported income.
The other common source of 24z entries is a deduction created by newer legislation that the IRS hasn’t yet assigned a dedicated line, or an adjustment arising from specific IRS guidance issued during the year. Because the contents shift as the form evolves, there’s no fixed list.
1099-K Reporting Has Changed
For tax years 2022 and 2023, taxpayers who received a Form 1099-K covering personal items sold at a loss were told to report the gross proceeds on Schedule 1, Line 8z and enter an offsetting negative amount on Line 24z to zero out the non-taxable portion.
That method no longer applies going forward. Starting with tax years beginning in 2024, you report 1099-K amounts in the entry space at the top of Schedule 1 rather than using the Line 8z and Line 24z offset. The old method still applies if you’re filing an amended return for 2022 or 2023.
How to Fill It In
Write a brief description of the adjustment in the space next to Line 24z and enter the dollar amount. Something like “IRC 136 energy subsidy exclusion” is enough to identify the item. If you have only one 24z adjustment, that description and amount on the form itself are all you need.
When you have more than one 24z adjustment, prepare a separate statement listing each one with its type and amount, attach it to the return, and enter only the combined total on Line 24z. The statement doesn’t use a specific IRS form number; it just needs to identify each adjustment clearly enough that an examiner can trace the math.
The Line 24z amount is added to Lines 24a through 24k to produce the Line 25 total. Line 25 then combines with the other Part II adjustments on Line 26, which flows to Form 1040 and reduces your gross income to arrive at AGI.
Because write-in adjustments without an explanation tend to get flagged for correspondence, attaching a short supporting statement is worth doing even when you have a single 24z entry. It costs nothing and heads off the most common processing delay.
Records and Penalty Exposure
Keep records supporting a Line 24z adjustment for at least three years from the date you filed the return or its due date, whichever is later, which aligns with the general statute of limitations for IRS assessments. If the adjustment relates to property basis, keep the records for as long as you own the property and for three years after you dispose of it.
A wrong 24z adjustment can trigger the accuracy-related penalty under IRC Section 6662, which adds 20% to any underpayment caused by negligence or a substantial understatement of tax. The penalty applies when the IRS determines you didn’t have a reasonable basis for the deduction. For uncommon adjustments of the kind that end up on 24z, the practical defense is a paper trail: the calculation, the statutory authority, and the documents proving the amount.