Title 26 › Subtitle Subtitle A— - Income Taxes › Chapter CHAPTER 1— - NORMAL TAXES AND SURTAXES › Subchapter Subchapter E— - Accounting Periods and Methods of Accounting › Part PART I— - ACCOUNTING PERIODS › § 441
You figure taxable income using the taxpayer’s taxable year. Taxable year — usually the annual accounting period the taxpayer uses to keep books, often a calendar or fiscal year, but it can also be the calendar year, a shorter return period, or a special period for a DISC. Annual accounting period — the yearly period the taxpayer uses for bookkeeping. Calendar year — any 12 months that end on December 31. Fiscal year — any 12 months that end on the last day of a month other than December, or a 52- to 53-week year if elected. If a taxpayer keeps no books, has no annual accounting period, or their accounting period doesn’t count as a fiscal year, the taxable year must be the calendar year. If a return covers less than 12 months, the taxable year is the return period. Taxpayers may use a 52- to 53-week year that always ends on the same weekday and either on that weekday’s last date in a month or the date nearest the month’s end; the Treasury can set rules for how this works for partnerships, S corporations, and personal service corporations. When changing to or from such a 52–53 week year, special rules apply: if a short period is 359 days or more, or under 7 days, an alternative tax computation does not apply; any short period under 7 days is added to the next year; if annualizing a short period is required, the gross income for the short period is multiplied by 365 and divided by the number of days in that short period. For a DISC, the taxable year is the same 12-month year as the shareholder or shareholder group with the largest voting power; if there is a tie, any tied shareholder’s year may be used, and the Treasury will make rules for ownership changes and how voting power is counted. A personal service corporation must use the calendar year unless it proves to the Treasury a real business reason for a different year; simply delaying income to shareholders is not a business reason.
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Internal Revenue Code — Source: USLM XML via OLRC
Legislative History
Reference
Citation
26 U.S.C. § 441
Title 26 — Internal Revenue Code
Last Updated
Apr 6, 2026
Release point: 119-73