Schedule 1 (Form 1040) + AI Agent Skill: Additional Income Guide 2026

Schedule 1 (Form 1040) reports income that has no line on Form 1040 itself (Part I, Lines 1-10) and the above-the-line adjustments that reduce AGI (Part II, Lines 11-26). The two totals land in fixed places: Line 10 (total additional income) flows to Form 1040 Line 8, and Line 26 (total adjustments) flows to Form 1040 Line 10. The most-searched line answers: Line 8d is the foreign earned income exclusion from Form 2555 (entered as a negative), Line 15 is the deductible half of self-employment tax, and Line 21 is student loan interest, capped at $2,500.

Key takeaways:

• Schedule 1 Line 10 → Form 1040 Line 8; Schedule 1 Line 26 → Form 1040 Line 10. Together they shape AGI
• Schedule C net profit lands on Line 3; half your SE tax deducts on Line 15
• Line 21 (student loan interest): up to $2,500, available with the standard deduction; 2026 phaseout starts at $85,000 MAGI single / $175,000 MFJ
• A 1099-K received in error or for personal items sold at a loss goes on the dedicated entry space at the very top of Schedule 1, above Part I
• Part II adjustments beat itemized deductions dollar-for-dollar because lower AGI also unlocks credits and softens phaseouts

Official IRS resources: Schedule 1 (Form 1040) (PDF) · Instructions (PDF) · About Schedule 1 (Form 1040)

Schedule 1 is the bridge between Form 1040 and the rest of your tax life. Anything that isn't W-2 wages, ordinary interest, dividends, or retirement distributions probably touches this schedule, and the above-the-line deductions that self-employed filers most often miss live here too.

What Is Schedule 1?

Schedule 1 (officially "Additional Income and Adjustments to Income") is an attachment to Form 1040, 1040-SR, or 1040-NR. It has two jobs:

• Part I reports income that doesn't fit on the main Form 1040 income lines (wages, interest, dividends, retirement, Social Security, capital gains)
• Part II reports adjustments, also called "above-the-line deductions," that reduce your gross income before the standard or itemized deduction is applied

Legal basis: IRC §61 defines gross income broadly. IRC §62 lists the specific deductions allowed in computing AGI; these are the items in Part II of Schedule 1.

Who Files Schedule 1?

You file Schedule 1 if:

• You received unemployment compensation
• You ran a side business or had self-employment income (Schedule C → Line 3)
• You had rental real estate, royalty, partnership, S-corp, or trust income (Schedule E → Line 5)
• You had farm income (Schedule F → Line 6)
• You received a state or local tax refund and itemized deductions in the prior year
• You received gambling winnings, jury duty pay, prizes, or hobby income
• You received digital assets (crypto, NFTs) as ordinary income
• You paid student loan interest, made HSA or SEP-IRA contributions, or paid self-employed health insurance premiums
• You paid alimony under a pre-2019 divorce decree (or received it under one)
• You owe self-employment tax; half of it is deductible on Line 15 (the tax itself is reported on Schedule 2)

You skip Schedule 1 if your only income is W-2 wages and standard interest/dividends, and you have no above-the-line adjustments.

The 1099-K Entry Space Above Part I

Before Line 1, Schedule 1 has a dedicated entry: amounts reported to you on Form(s) 1099-K in error or for personal items sold at a loss (used furniture on Facebook Marketplace, concert tickets reimbursed via PayPal Goods & Services). Entering the amount there tells the IRS not to treat the whole 1099-K as taxable income. A 1099-K for real trade or business activity (regular Etsy sales, rideshare, freelance gigs) does NOT go there; that income belongs on Schedule C, whose net profit flows to Line 3.

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Schedule 1 Key Numbers: 2025 and 2026

The form structure is fixed: Part I has Lines 1-10, Part II has Lines 11-26. The numeric limits attached to specific lines are now final for both years.

Alimony caveat: the rules depend on the divorce decree date, not the tax year. Pre-2019 decrees use the old rules (deductible for the payer, taxable for the recipient); post-2018 decrees use TCJA rules (neither).

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Part I: Additional Income (Line by Line)

Part I aggregates every income source that isn't on the main Form 1040 income lines.

Line 1: Taxable Refunds, Credits, or Offsets of State and Local Income Taxes

A state or local income tax refund is taxable only if you itemized deductions in the prior year and got a tax benefit from deducting state income taxes. If you took the standard deduction last year, your refund is not taxable and doesn't go on Line 1.

If you did itemize, use the worksheet in IRS Publication 525 and consider the SALT cap interaction: if the cap was already maxed by property tax, the state income tax deduction may not have produced a benefit, making the refund non-taxable.

Line 2a: Alimony Received

Alimony received under a divorce or separation agreement executed before January 1, 2019 is reported here. For agreements executed after December 31, 2018, alimony received is not taxable income and doesn't appear on Schedule 1; TCJA repealed the income inclusion for post-2018 decrees.

Line 2b is a date field for the original decree.

Legal basis: IRC §71 (pre-TCJA rules, still apply to pre-2019 decrees).

Line 3: Business Income or (Loss)

Line 3 is your net profit or loss from Schedule C. If you ran a sole proprietorship or single-member LLC, Schedule C Line 31 flows here: positive if a profit, in parentheses if a loss.

For a complete walk-through of Schedule C, see our Schedule C Instructions Guide 2026.

Line 4: Other Gains or (Losses) from Form 4797 or 4684

Line 4 carries gains and losses from Form 4797 (sales of business property) and Form 4684 (casualties and thefts); the 2025 revision added checkboxes to mark which form the amount comes from. Most solo filers leave this blank. Note the boundary: capital assets go on Form 8949/Schedule D, business-use property on Form 4797.

Line 5: Rental Real Estate, Royalties, Partnerships, S Corporations, Trusts

Net result from Schedule E. This includes:

• Residential rental property income/loss
• Royalty income from books, music, mineral rights, etc.
• Income from partnerships (K-1)
• Income from S corporations (K-1)
• Income from estates and trusts (K-1)

If you own a rental as a sole proprietor (not as a real estate dealer), the income belongs on Schedule E, not Schedule C, and Schedule E flows here.

Line 6: Farm Income or (Loss)

From Schedule F. Farmers report on Schedule F instead of Schedule C; the net result lands on Line 6.

Line 7: Unemployment Compensation

Total unemployment compensation received during the year, reported to you on Form 1099-G Box 1. State and federal unemployment benefits are both taxable at the federal level. If you repaid an overpayment during the same year, check the box and enter the amount repaid.

Pandemic-era exclusions (the $10,200 exclusion for 2020) are long expired; all unemployment compensation is taxable now.

Line 8: Other Income (8a through 8z)

Line 8 is the catchall for income types that don't fit Lines 1-7, split into lettered sub-lines. The most common for solo filers:

Line 9: Total Other Income

Add Lines 8a through 8z. Some lines (8a, 8d, 8s) are entered as negatives, so the sum can be negative.

Line 10: Total Additional Income → Form 1040 Line 8

Schedule 1 Line 10 combines Lines 1 through 7 plus Line 9; it is your total additional income, and it is entered on Form 1040 Line 8. From there it joins wages, interest, dividends, retirement income, and capital gains in the Form 1040 Line 9 total.

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Part II: Adjustments to Income (Above-the-Line Deductions)

Part II is where above-the-line deductions live. These reduce AGI whether or not you itemize, which makes them more valuable than the same dollar of itemized deduction: lower AGI also improves credit eligibility and softens phaseouts. Estimate the ripple effect with our AGI calculator.

Line 11: Educator Expenses

Up to $300 (2025) or $350 (2026) for unreimbursed classroom expenses by K-12 teachers, counselors, principals, and aides who worked at least 900 hours in a school year. Eligible expenses include books, supplies, computer equipment, and professional development.

Legal basis: IRC §62(a)(2)(D).

Line 12: Reservists, Performing Artists, Fee-Basis Government Officials

Three narrow groups deduct unreimbursed business expenses above the line via Form 2106: Armed Forces reservists traveling 100+ miles for reserve duty; qualifying performing artists; and state/local government officials paid on a fee basis. Most filers leave this blank.

Line 13: Health Savings Account (HSA) Deduction

If you contributed to an HSA outside of payroll, the contribution deducts here via Form 8889. Limits: $4,300 self-only / $8,550 family for 2025; $4,400 / $8,750 for 2026, plus a $1,000 catch-up at 55+. You must be enrolled in a qualifying high-deductible health plan. Contributions made through payroll are already excluded from W-2 Box 1 wages and do not go here.

Legal basis: IRC §223; IRS Publication 969; Rev. Proc. 2025-19 (2026 limits).

Line 14: Moving Expenses for Members of the Armed Forces

Active-duty service members moving on permanent change of station orders deduct moving expenses on Form 3903 → Line 14 (a checkbox covers storage-fee-only claims). TCJA suspended the civilian moving deduction, and OBBBA made that permanent; civilians cannot deduct moving expenses.

Line 15: Deductible Part of Self-Employment Tax

Half of the SE tax you owe (calculated on Schedule SE) deducts here: the "employer-equivalent" portion of FICA. Example: $80,000 Schedule C profit × 0.9235 × 0.153 = $11,304 SE tax; half = $5,652 on Line 15. The flow: Schedule SE Line 13 → Schedule 1 Line 15. Model your own numbers with the self-employment tax calculator. Legal basis: IRC §164(f).

Line 16: Self-Employed SEP, SIMPLE, and Qualified Plans

Contributions to retirement plans for the self-employed: SEP-IRA (25% of net SE earnings, capped at $70,000 for 2025 / $72,000 for 2026); SIMPLE IRA; Solo 401(k) (employer + employee portions for owner-employees). Contributions for your employees go on Schedule C Line 19, not here.

Line 17: Self-Employed Health Insurance Deduction

Health, dental, and qualified LTC premiums paid by a self-employed person for themselves, spouse, dependents, and children under 27. Limited to net Schedule C profit. Disqualifier: you cannot claim this for any month you or your spouse were eligible for an employer-subsidized plan.

For a deeper walk-through, see our Health Insurance Deduction Guide for Self-Employed 2026. Legal basis: IRC §162(l).

Line 18: Penalty on Early Withdrawal of Savings

If you cashed out a CD or savings instrument before maturity and incurred an early withdrawal penalty, the penalty is deductible here. The bank reports it on Form 1099-INT Box 2.

Line 19a: Alimony Paid

Alimony paid under a pre-2019 divorce decree is deductible. Post-2018 decrees: no deduction, mirroring the no-inclusion rule for the recipient. Lines 19b and 19c capture the recipient's SSN and the original decree date.

Line 20: IRA Deduction

Traditional IRA contributions, subject to deduction phase-outs when you (or your spouse) are covered by an employer retirement plan. Roth IRA contributions are not deducted here (they're after-tax). If you're married filing separately and lived apart from your spouse the entire year, check the box.

Line 21: Student Loan Interest Deduction

Up to $2,500 of interest paid on qualified student loans. The MAGI phaseout for 2025: $85,000–$100,000 single, $170,000–$200,000 MFJ; for 2026: $85,000–$100,000 single, $175,000–$205,000 MFJ. Your lender reports the interest on Form 1098-E. Line 21 works alongside the standard deduction, which is exactly why it's one of the most-missed adjustments. Legal basis: IRC §221.

Line 22: Reserved for Future Use

Currently blank. The IRS reserves line numbers for future legislative changes.

Line 23: Archer MSA Deduction

Archer Medical Savings Accounts predate HSAs and are largely closed to new entrants. Contributions deduct via Form 8853. Most filers leave Line 23 blank; HSAs (Line 13) replaced this for new contributors.

Line 24: Other Adjustments (24a through 24z)

Catchall for adjustments that don't fit Lines 11-23:

Line 25: Total Other Adjustments

Sum of 24a through 24z.

Line 26: Total Adjustments to Income → Form 1040 Line 10

Schedule 1 Line 26 adds Lines 11 through 23 plus Line 25; it is your total adjustments to income, and it is entered on Form 1040 Line 10, where it subtracts from total income to produce AGI.

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How Schedule 1 Flows Into Form 1040

The two Schedule 1 totals land in two specific places:

Form 1040 then computes: Line 9 (total income) minus Line 10 (adjustments) = Line 11a (AGI); AGI minus the standard or itemized deduction (Line 12e) and the QBI deduction (Line 13a) = Line 15 (taxable income).

The math chain matters because AGI is the gating number for much of the return: IRA deduction phaseouts, the student loan interest phaseout, the premium tax credit, the Saver's Credit, and the 7.5% medical floor on Schedule A. A dollar of Schedule 1 Part II adjustment is worth at least as much as a dollar of itemized deduction, and usually more.

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Worked Example: Nora the Freelance Designer with Side Gig Income

Nora runs a freelance graphic design business as a sole proprietor and sells digital prints on Etsy. Her 2026 numbers:

• Schedule C net profit (freelance + Etsy combined): $40,000 (gross $48,500 − $8,500 expenses)
• Student loan interest paid (Form 1098-E): $700
• Self-employed health insurance (marketplace ACA): $4,200
• SEP-IRA contribution: $1,500

Self-employment tax first (feeds Line 15): net SE earnings = $40,000 × 0.9235 = $36,940. SE tax = $36,940 × 15.3% = $5,652. Half of SE tax = $2,826 → Line 15.

Nora's Schedule 1

How Nora's Numbers Flow into Form 1040 (2026, single, no W-2)

QBI note: the deduction is the lesser of 20% of qualified business income ($40,000 minus the Line 15/16/17 adjustments = $31,474; × 20% = $6,295) or 20% of taxable income before QBI ($30,774 − $16,100 = $14,674; × 20% = $2,935). The taxable-income limit wins.

Federal income tax on $11,739 sits entirely in the 2026 10% bracket (which runs to $12,400 for single filers): about $1,174. Add the full $5,652 SE tax (the Line 15 deduction reduces income tax, not SE tax itself) for a total federal bill around $6,826.

Without the $9,226 of Part II adjustments, Nora's taxable income would have been roughly $9,200 higher, costing her over $1,000 in extra income tax plus a smaller QBI deduction. The adjustments were four lines of the form.

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Common Mistakes to Avoid

Mistake #1: Reporting Hobby Income With Expense Offsets

Problem: A filer with $5,000 hobby income on Line 8j deducts $4,000 of hobby expenses to net $1,000.

Impact: Under TCJA, hobby expenses are not deductible. Netting understates taxable income and triggers an IRS adjustment.

Solution: Report gross hobby income on Line 8j. If the activity is regular and for-profit, it's a trade or business: file Schedule C instead, where expenses do deduct.

Mistake #2: Forgetting the Student Loan Interest Deduction

Problem: A filer with $1,800 of student loan interest takes the standard deduction and skips Line 21, assuming "I didn't itemize so I can't deduct anything."

Impact: $1,800 deduction missed → roughly $396 of tax overpaid at the 22% bracket.

Solution: Line 21 is above-the-line, available regardless of standard vs itemized. If MAGI is below $100,000 single ($205,000 MFJ for 2026), claim it.

Mistake #3: Missing the Self-Employed Health Insurance Deduction

Problem: A self-employed filer paid $6,000 in marketplace ACA premiums but didn't put it on Line 17 because "I deducted it on Schedule C."

Impact: Owner health insurance doesn't belong on Schedule C. If it was also added to Schedule C, that's a second error (overstated business expense).

Solution: Owner health insurance goes on Schedule 1 Line 17, not Schedule C Line 14 (Line 14 is for employee benefits). Limited to net Schedule C profit. See our Health Insurance Deduction Guide 2026.

Mistake #4: Double-Counting Schedule C Profit

Problem: A filer reports Schedule C net profit of $50,000 on Line 3, and separately adds $50,000 of "self-employment income" on Line 8z.

Impact: $50,000 of phantom income and phantom SE tax.

Solution: Schedule C net profit goes on Line 3 only. Schedule SE is a parallel calculation, not duplicate income.

Mistake #5: Reporting a State Refund as Taxable When It Isn't

Problem: A filer who took the standard deduction last year reports a $400 state refund on Line 1 this year.

Impact: $400 phantom income, roughly $88 unnecessary tax at the 22% bracket.

Solution: A state refund is taxable on Line 1 only if you itemized last year and got a tax benefit from deducting state income tax. After the standard deduction, leave Line 1 blank.

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No Missed Adjustments: How Jupid Helps

Part I gets reported because the IRS already holds matching 1099s; Part II gets skipped because nothing reminds filers about it. Jupid closes that gap from your bank feed: the 1098-E from your loan servicer, marketplace ACA premium charges, and SEP-IRA transfers are recognized and tagged to their Schedule 1 lines automatically, while business expenses route to Schedule C at 95.9% categorization accuracy so the Line 3 number is defensible. Ask the AI accountant in WhatsApp or iMessage "what goes on Schedule 1 for me this year?" and get the line-by-line answer built from your real transactions.

Try Jupid

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Action Checklist: Filing Schedule 1

• Collect every 1099 and map it to its line: 1099-G unemployment → Line 7; 1099-G state refund → Line 1 (only if you itemized); 1099-NEC business → Schedule C → Line 3
• Enter any erroneous or personal-loss 1099-K amount on the dedicated space above Part I
• Complete Schedule C and Schedule SE first; they feed Lines 3 and 15
• Enter HSA contributions made outside payroll on Line 13 via Form 8889 ($4,400 / $8,750 limits for 2026)
• Enter SEP-IRA / Solo 401(k) contributions on Line 16 and marketplace health premiums on Line 17
• Pull Form 1098-E and claim student loan interest on Line 21 if MAGI allows
• Cross-check the two totals: Line 10 → Form 1040 Line 8; Line 26 → Form 1040 Line 10

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Resources and Citations

IRS Forms and Instructions

• Schedule 1 (Form 1040): Additional Income and Adjustments to Income
• Form 1040 Instructions: General instructions covering Schedule 1 line by line
• About Schedule 1: IRS landing page with current and prior-year revisions
• Form 8889: Health Savings Accounts (HSAs)
• Form 1098-E: Student Loan Interest Statement
• Form 2555: Foreign Earned Income (feeds Lines 8d and 24j)

IRS Publications

• Publication 17: Your Federal Income Tax (For Individuals)
• Publication 525: Taxable and Nontaxable Income
• Publication 969: Health Savings Accounts and Other Tax-Favored Health Plans
• Publication 970: Tax Benefits for Education (covers student loan interest)

Tax Code References

• IRC §61: Definition of gross income
• IRC §62: Adjusted gross income (above-the-line deductions list)
• IRC §71: Alimony (pre-2019 decrees)
• IRC §162(l): Self-employed health insurance deduction
• IRC §164(f): Half of self-employment tax deduction
• IRC §221: Student loan interest deduction
• IRC §223: Health Savings Account contributions

Year-Specific Authority

• Rev. Proc. 2024-25: 2025 HSA contribution limits
• Rev. Proc. 2024-40: 2025 inflation adjustments (educator cap, student loan phaseout)
• Notice 2024-80: 2025 retirement plan contribution limits
• Rev. Proc. 2025-19: 2026 HSA contribution limits
• Rev. Proc. 2025-32: 2026 inflation adjustments

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Final Thoughts

Schedule 1 is where Form 1040 stops being a single page and starts being the real return. Part I gets reported because the IRS already has matching 1099s, but Part II gets skipped because nobody reminds filers about above-the-line adjustments. The four adjustments solo filers miss most often — half of SE tax (Line 15), SE health insurance (Line 17), SEP-IRA contributions (Line 16), and student loan interest (Line 21) — routinely shave $5,000-$15,000 off AGI for a mid-five-figure freelancer.

Key strategies:

1. Treat Schedule 1 as required: every solo filer with self-employment income files it.
2. Map every 1099 to a Schedule 1 line first: 1099-G unemployment → Line 7; 1099-G state refund → Line 1 (if itemized prior year); 1099-MISC prize → Line 8i; 1099-NEC business → Schedule C → Line 3.
3. Run the AGI math both ways: with and without Part II adjustments, because AGI drives credits and phaseouts across the whole return.

Use This with Your AI Agent

If you're using Claude, ChatGPT, or another AI agent to help fill out Schedule 1 (Form 1040), we've published an open-source skill that gives the agent exact line-by-line instructions, validation checks, ask-don't-guess prompts, and worked examples — the same logic Jupid uses internally.

→ jupid-tax/jupid-skills on GitHub — forms/schedule-1/

For Claude Code: cp -r jupid-skills/forms/schedule-1 ~/.claude/skills/. For the Anthropic SDK, load SKILL.md into the system prompt and the references/ files on demand. For browser-automation runtimes, filing.md covers the e-file or paper-file workflow.

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Disclaimer

This article provides general information about Schedule 1 of Form 1040 and should not be considered tax advice. Tax laws change frequently and individual circumstances vary. 2025 figures are from Rev. Proc. 2024-40 and Rev. Proc. 2024-25; 2026 figures are from Rev. Proc. 2025-32 and Rev. Proc. 2025-19. For advice specific to your situation, consult with a qualified tax professional.

Tax Years: 2025 (returns filed in 2026) and 2026 Last Updated: July 7, 2026