### Question
How does the law define barrel?


### Answer
Under *26 U.S.C. § 29*, **barrel** is defined as:

> 42 United States gallons

#### Citation:
  - *26 U.S.C. § 29*
  - Heading: **Subtitle A-Income Taxes > CHAPTER 1-NORMAL TAXES AND SURTAXES > Subchapter A-Determination of Tax Liability > PART IV-CREDITS AGAINST TAX > Subpart B-Other Credits**

