### Question
How does SUBCHAPTER A—INCOME TAX (Continued) define calendar year?


### Answer
Under *26 CFR § 1.441-1T*, **calendar year** is defined as:

> a period of 12 months ending on December 31. A taxpayer who has not established a fiscal year must make his return on the basis of a calendar year

#### Citation:
  - *26 CFR § 1.441-1T*
  - Heading: **Title 26—Internal Revenue > PART 1—INCOME TAXES (Continued) > CHAPTER I—INTERNAL REVENUE SERVICE, > SUBCHAPTER A—INCOME TAX (Continued) > SUBCHAPTER A—INCOME TAX (Continued)**

