### Question
How is the "annual accounting period" defined?


### Answer
The term **annual accounting period** is defined in *26 CFR § 1.441-1T* as follows -

> the annual period (calendar year or fiscal year) on the basis of which the taxpayer regularly computes his income in keeping his books

#### Citation:
  - *26 CFR § 1.441-1T*
  - Heading: **Title 26—Internal Revenue > PART 1—INCOME TAXES (Continued) > CHAPTER I—INTERNAL REVENUE SERVICE, DEPARTMENT OF THE TREASURY(CONTINUED)**

