Pub 17 chapter 1 in plain English: do you have to file?
Do you have to file a tax return? Chapter 1 of Publication 17 answers that and covers due dates, late costs, records and corrections. These notes cover tax years 2023 to 2025 and look ahead to 2026.
Prepared by Prem Tax and Accounting Corp. Last checked against official sources on October 26, 2026.
Chapter 1 covers printed pages 6 to 21 of Publication 17 (2025), and the same stretch of the 2023 and 2024 editions. It asks whether you have to file, by when, and what filing late costs. Think of this page as a friendly summary; the IRS publication has the last word.
- Your gross income, filing status and age on December 31 decide whether you must file.
- Net self-employment earnings of $400 or more require a return in 2023, 2024 and 2025.
- A return is also how withheld tax and refundable credits come back to you.
- An extension gives more time to file, not more time to pay.
Who must file
Gross income is everything you received as cash, goods, property or services that the law does not exempt. Compare your total with the table below. Certain special taxes can also trigger a return.
A single dependent under 65 and not blind must file with unearned income over $1,250 (2023), $1,300 (2024) or $1,350 (2025). File anyway if tax was withheld or you qualify for a refundable credit.
Deadlines and late costs
Most people file by April 15 after the tax year. Form 4868 adds six months to file (October 15 for calendar-year filers), but not to pay; interest runs from April 15.
Filing late usually costs 5 percent of the unpaid tax per month or part month, up to 25 percent. Paying late costs half of 1 percent per month, also up to 25 percent (all years). Past 60 days late, a floor applies: the smaller of a set amount or all the unpaid tax.
Records and corrections
Keep records until the time limit for the return ends: usually 3 years from filing, 6 if you left out over 25 percent of the gross income shown. A refund claim generally goes in within 3 years of filing or 2 years of paying, whichever is later, on Form 1040-X.
Numbers by year
| Tax year | Single, under 65 | Married joint, both under 65 | Return due | Late-filing floor |
|---|---|---|---|---|
| 2023 | $13,850 | $27,700 | April 15, 2024 (April 17 in Maine and Massachusetts) | $485 |
| 2024 | $14,600 | $29,200 | April 15, 2025 | $510 |
| 2025 | $15,750 | $31,500 | April 15, 2026 | $525 |
| 2026 planning | not yet published | not yet published | April 15, 2027 | $535 |
The middle columns are gross income amounts (file at that amount or more); age 65 or older raises them (single, 2025: $17,750). The floor is the smaller of that amount or 100 percent of the unpaid tax. For 2026, treat the numbers as planning figures (source: Rev. Proc. 2025-32 and the 2025 law), since the IRS has not issued Pub 17 (2026). The 2026 thresholds are blank because that Rev. Proc. sets the standard deduction, not the filing thresholds. See our tax calendar.
An invented example
Invented, tax year 2025. Dana, single, 34 and claimed by no one, earned $14,900 in wages and $1,200 in bank interest, with $600 withheld. Gross income is $14,900 + $1,200 = $16,100, which is $350 over the $15,750 amount, so she must file. With wages alone she would be under it, yet would file to recover the $600.
Mistakes people make
- Thinking "I owe nothing" means "I need not file."
- Treating an extension as time to pay.
- Missing side income that reaches $400 of net self-employment earnings.
- Expecting a paper refund check; the 2025 edition says that, with exceptions, the IRS is phasing out paper refund checks from October 2025.
Quick check
Single, 40, gross income $14,000, $500 withheld: must she file? (2024)
Answer: No. $14,000 is under the 2024 amount of $14,600. She would file only to recover the $500.
A married couple filing jointly, both 66, with gross income of $33,500: must they file on income alone? (2025)
Answer: No. The 2025 amount is $34,700, and $34,700 - $33,500 = $1,200 of room.
A return is filed 70 days late and the unpaid tax is $380. What is the floor? (2025)
Answer: $380, because the floor is the smaller of $525 or 100 percent of $380.
Common questions
How long should I keep records?
Usually 3 years from filing. Keep property records until the limit ends for the year you sell it.
Can I still get a refund if I never filed?
Generally only if you file within 3 years of the due date, extensions included.
How do I fix a return I filed?
File Form 1040-X. Pub 17 (2025) says claims usually take 8 to 12 weeks, an estimate rather than a promise.
Official sources
- IRS Publication 17 (2025), chapter 1
- IRS Publication 17 (2024), chapter 1
- IRS Publication 17 (2023), chapter 1
- IRS Revenue Procedure 2025-32 (2026 inflation adjustments)
Keep reading
- Filing Status Rules (Pub 17 Chapter 2)
- Withholding and Estimated Tax (Pub 17 Chapter 4)
- Key Tax Numbers by Year, 2023 to 2026
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