Pub 17 Study Notes, Chapter 1: Filing Information (Tax Years 2023 to 2026)

Chapter 1 of IRS Publication 17 covers the basics of any return: whether you must file, how and when, signing, paying, refunds, records, amending and penalties. It runs from page 6 to part-way down page 21 of the 2025 edition; the 2023 and 2024 editions have the same chapter. It touches Form 1040 and 1040-SR, Schedules 1, 3 and SE, and Forms 4868, 8453, 8879, 8888, 8379, 9465, 1040-X and 8822. It suits preparers, exam candidates (Enrolled Agent, IRS SEE, AFSP) and filers checking their own duties. Next is chapter 2, filing status. These are unofficial study notes in our own words; the IRS publication controls. Rules are the same in all years unless a year is named.

Key terms

Who must file

Citizens and residents (including Puerto Rico residents) must file when they meet the test for their category, even owing nothing. File one original return per year.

The general test (p. 7)

1. Total gross income, including excludable foreign income and home-sale gain. Use business receipts (Schedule C line 7, Schedule F line 9), not profit.
2. Add the taxable part of Social Security only if you are married filing separately and lived with your spouse at any time in the year, or half your benefits plus other income and tax-exempt interest exceeds $25,000 ($32,000 joint).
3. Use your December 31 status and year-end age, then compare with the by-year table below. A joint filer who did not live with the spouse at year-end and had $5 of income must file at any age.

Apart from separate filers, Table 1-1 is the standard deduction plus the age add-on, so the senior deduction does not lower it.

At any income (Table 1-3, p. 10)

• Schedule 2 taxes (alternative minimum tax, extra tax on IRAs, household employment tax, tax on unreported tips, recapture) and HSA or MSA distributions.
• Net self-employment earnings of $400 or more, or $108.28 or more of church wages.
• Advance premium tax credit, section 965 amounts, or a clean vehicle credit transferred to a dealer (listed from 2024).

Special groups

• Dependents use Table 1-2: unearned, earned and total income tests. Married dependents also file at $5 if the spouse files separately and itemizes.
• Children file their own returns; a parent signs for one who cannot and owes if the child does not pay. Form 8814 lets parents report a child whose only income is interest and dividends (under 19, or a student under 24, and other conditions are met).
• Others: resident aliens follow citizen rules; nonresidents use Pub. 519. A decedent's final return is due if the threshold was met. Community property states split income by state law (Form 8958). See how much income you need to file.

File anyway to recover withholding or claim the earned income credit, additional child tax credit, premium tax credit, American opportunity credit or (listed from 2025) refundable adoption credit.

Filing electronically and signing

• E-file confirms acceptance and does not change audit odds. Free routes: Free File software (income-limited), Free File Fillable Forms (anyone), VITA (2025 edition: generally AGI of $69,000 or less; 2024: under $67,000; 2023: $64,000 or less) and TCE (aimed at 60 and over). Direct File is described in chapter 1 of the 2024 edition only.
• Self-Select PIN: five digits, not all zeros, one per spouse, verified with last year's AGI from the original return (Form 1040 line 11 through 2024, line 11a on the 2025 form) or last year's PIN. Not for first-time filers under 16. Practitioner PIN: the preparer enters it under Form 8879.
• IP PIN: open to everyone; if issued, all six digits are required. Form 8453 is mailed when an attachment cannot be e-filed.
• Paper returns need a handwritten signature, and both spouses sign a joint return.
• An agent may sign under a power of attorney (Form 2848 stating signing authority) if you are ill or injured, abroad 60 or more days straight before the due date, or the IRS agrees.
• Paid preparers sign with a PTIN and give you a copy. A third party designee can discuss processing but cannot take your refund or bind you.

When and where to file

The due date is the 15th day of the fourth month after year-end; weekends and holidays roll forward. Paper is on time if postmarked by then (listed private carriers count, but not for P.O. boxes). E-file uses the transmitter's postmark in your time zone. With a refund due but no return filed, you generally lose it 3 years after the due date.

Extensions

1. Automatic 6 months: Form 4868 by the due date, or pay by card or bank transfer. Report the payment on Schedule 3 line 10. See filing extensions.
2. Abroad: citizens and residents living and working outside the U.S. and Puerto Rico, or on military duty abroad, get 2 months (attach a statement); Form 4868 line 8 adds 4.
3. Combat zone: deadlines extend 180 days after the later of your last day in the zone or qualifying hospitalization, plus days left when you entered.

Most individuals use a calendar year and the cash method, counting income when actually or constructively received.

SSNs, ITINs and identity

• Enter the SSN of you, your spouse (same order as the names) and every dependent of any age. Report name changes to SSA first.
• Certain benefits are lost without an SSN or ITIN issued by the due date, extensions included. A child's SSN must also be valid for work (chapter 14).
• ATIN (Form W-7A) covers pending adoptions.
• ITIN: Form W-7 with the return, about 7 weeks. Unused on a return for three tax years it expires. An ITIN return cannot be e-filed in the year the ITIN is issued. See ITINs.
• A missing required SSN costs $50 each. If misused, answer IRS notices and consider an IP PIN.

Paying what you owe

Pay with the return; nothing is due under $1. Options: Direct Pay, EFTPS, card (fee), cash, or check or money order with Form 1040-V. Per IRS fact sheet FS-2026-02, individuals could not open new EFTPS enrollments after October 17, 2025, and all individuals are to move off EFTPS later in 2026. A dishonored payment costs $25 or 2%, whichever is larger.

Interest starts at the due date even with an extension and resets quarterly from the federal short-term rate (that rate plus 3 points for individuals' underpayments). On late-filing, accuracy and fraud penalties it runs from the due date, extensions included. Installment agreements (Form 9465 or online) add a fee; interest and penalty continue. See installment agreements.

Refunds

• Take the refund or credit it to next year's estimated tax; after the due date the choice is final.
• Direct deposit may go to checking, savings, HSA, brokerage or a traditional or Roth IRA (not SIMPLE), in your name. Limit: three refunds a year per account or card. Form 8888 splits a refund.
• Paper checks: Executive Order 14247 (March 25, 2025) has Treasury stop issuing paper checks, tax refunds included, from September 30, 2025, to the extent permitted by law. The IRS says it began phasing out paper refund checks on that date; its fact sheet FS-2026-02 says it generally stopped them for individuals after September 30, 2025, with limited exceptions such as hardship or legal and procedural requirements. Pub. 17 (2025) words it as "starting in October 2025." With no bank details on the return, the IRS mails a letter (CP53E) asking for them within 30 days; with no reply and no other issue, the fact sheet says a paper check follows after six weeks. Savings-bond purchases ended after the 2023 edition.
• Offsets can take a refund for past-due federal tax, state income tax, support or student loans. Status shows 24 hours after e-file or 4 weeks after paper (where is my refund). No refund interest if paid within 45 days of the due date or filing.

Records and limitation periods

Keep records of income, deductions, credits and basis for the period of limitations (Table 1-6; Table 1-7 in the 2023 and 2024 editions).

Keep property records until the period ends for the year you dispose of it. See how long to keep records and the statute of limitations.

Amending and claiming a refund

Use Form 1040-X (one per year) for missed income, wrong or missed deductions and credits, or a wrong filing status. After the due date a joint return cannot be split. The 2024 and 2025 editions allow e-filing for the current and two prior years.

• Withholding and estimates count as paid on the due date.
• A claim within 3 years of filing recovers tax paid in that window plus any extension; later claims, only the last 2 years.
• Financial disability pauses the clocks. A protective claim is written and signed, names the years and describes the contingency.
• You may sue after denial or 6 months without action, within 2 years of the denial notice. See amended returns.

Penalties

• Failure to file: 5% of unpaid tax per month or part, max 25% (15%, max 75%, if fraud). Over 60 days late, the minimum is the smaller of $525 (2025 return) or 100% of the tax.
• Failure to pay: 0.5% a month, max 25%; 0.25% under an installment agreement (if you filed on time); 1% after a notice of intent to levy or a demand for immediate payment. No penalty during the automatic extension if you paid 90% of the real tax by the due date and pay the rest with the return.
• Accuracy-related: 20% of the underpayment (40% for certain undisclosed transactions). Substantial understatement means over the larger of 10% of correct tax or $5,000; Form 8275 discloses a position.
• Other: erroneous refund claim 20%; frivolous submission $5,000; civil fraud 75%.

Reasonable cause can excuse most of these. See the failure-to-file and failure-to-pay pages.

By tax year: 2023, 2024, 2025 and 2026

Married filing separately is $5 every year. A QSS aged 65+ matches a joint filer with one spouse 65+. A single dependent under 65 and not blind also files if gross income exceeds the larger of the unearned figure or earned income plus $400 (2023) or $450 (later years); earned income counts up to $13,450, $14,150, $15,300 and $15,650 for 2023 to 2026.

2026 column: planning figures from Rev. Proc. 2025-32 and the 2025 law; Pub 17 (2026) is not yet published. The 2026 thresholds and dependent figures are our sums of the 2026 standard deduction and age add-on; the $535 minimum is from the Rev. Proc.

Rule changes by edition

• 2023: Maine and Massachusetts had until April 17. Refunds could buy savings bonds.
• 2024: Direct File appears; savings-bond refunds go. Table 1-3 adds the dealer-transferred clean vehicle credit.
• 2025: Trump accounts and Form 4547 are new. Direct File drops out. The paper refund check phase-out is noted (IRS start date September 30, 2025).
• 2026 (planning): the draft 2026 Form 1040 adds a citizenship and work-authorization question (draft, may change).

Worked examples

Example 1 (tax year 2025). Maya, single, 40, earned $11,000 in wages and had freelance receipts of $5,000 against $3,500 of expenses. Gross income is $11,000 + $5,000 = $16,000, at least $15,750, so she must file. Her $1,500 profit also passes the $400 test.

Example 2 (tax year 2025). Noor, 19, a dependent, earned $6,000 and had $200 of interest. Unearned $200 is under $1,350; earned $6,000 is under $15,750; gross $6,200 is under the larger of $1,350 or $6,000 + $450 = $6,450. She need not file. With $1,500 of interest she must.

Example 3 (tax year 2025). Raj owed $4,000 on April 15, 2026, and filed and paid on July 20, 2026 (4 months or part). Filing: 4 x 4.5% x $4,000 = $720. Payment: 4 x 0.5% x $4,000 = $80. Total $800 plus interest. The $525 minimum is below $720, so it does not apply.

Common mistakes and exam traps

• Testing the threshold with profit or take-home pay instead of gross income.
• Treating an extension as time to pay.
• Signing an e-file with AGI from an amended return.
• Adding 5% and 0.5% to get 5.5%; the combined monthly rate is 5%.
• Counting 3 years from the day an early return was actually filed; the clock starts at the due date.

Forms and lines map

Check yourself

(2025) A single 40-year-old has $15,000 of gross income and no special triggers. Must she file?

Answer: No. The threshold is $15,750.

(2024) A single person born January 1, 1960, has $16,600 of gross income. Must he file?

Answer: Yes. He counts as 65 for 2024, so the threshold is $16,550.

(2025) A return is 90 days late with $300 of unpaid tax. What is the minimum late-filing penalty?

Answer: $300, the smaller of $525 or 100% of the tax.

(2023) Li filed his 2023 return on February 10, 2024. By when can he claim a refund?

Answer: April 15, 2027: the early return counts as filed April 15, 2024, plus 3 years.

(2025) What does e-filing Form 4868 on April 10, 2026 extend?

Answer: Filing, to October 15, 2026; not payment.

(2025) Which e-file PIN method is barred for a first-time filer aged 15 at year-end?

Answer: Self-Select PIN; first-time filers under 16 cannot use it.

(all years) What limitation period applies if over 25% of gross income was omitted?

Answer: 6 years. Fraud or no return has no limit.

(2025) A joint refund is offset for one spouse's old debt. Which form protects the other spouse?

Answer: Form 8379. Form 8857 is the separate innocent spouse request.

Frequently asked questions

General information only, not tax, legal or accounting advice for your situation. Rules, limits and deadlines change; confirm the current rules with the official source or a qualified professional before you act. Reading this page does not create a professional relationship with CPA Tax Payroll and Accounting Corp.