### Question
How is the term applicable base defined?


### Answer
The term **applicable base** is defined in *26 U.S.C. § 3231* as the following:

> for any calendar year the contribution and benefit base determined under section 230 of the Social Security Act for such calendar year

#### Citation:
  - *26 U.S.C. § 3231*
  - Heading: **Subtitle C-Employment Taxes > CHAPTER 22-RAILROAD RETIREMENT TAX ACT > Subchapter D-General Provisions**

