Overview
A trillion is a name for a very large whole number. In the short scale used in modern American and most English-language contexts, a trillion equals 1,000,000,000,000 (one thousand billion), written in scientific notation as 10^12. In other naming systems, historically used in parts of Europe, the same word has referred to a different power of ten; see the section on scale differences below.
Numeric forms and notation
Common ways to represent a trillion include the full digit grouping 1,000,000,000,000, the scientific form 1×10^12, and the metric-derived prefix "tera" (symbol T), which denotes a factor of 10^12. Financial tables and informal contexts sometimes abbreviate the term as "1T".
Scale differences and terminology
Two naming conventions have existed: the short scale and the long scale. In the short scale (now standard in the United States and many other countries), trillion = 10^12. In the long scale tradition, which was used historically in parts of Europe, trillion could mean 10^18. Because of this potential for confusion, writers and translators may clarify by giving a numeric expression or using scientific notation.
Examples and relative size
- One trillion seconds is on the order of 31,700 years, illustrating the large temporal span the number represents.
- National budgets, gross domestic product (GDP) figures and government debt are often discussed in trillions of currency units.
- In computing and data storage, a terabyte (1 TB) is marketing-related and may be reported using either decimal (10^12) or binary conventions.
History and etymology
The -illion family of names (million, billion, trillion, etc.) developed in Europe by extending the word "million" with prefixes to indicate larger powers. Over time the short and long scales diverged in use; many languages and countries have standardized on the short-scale meanings for clarity in international communication.
For a concise numeric definition and related terminology, see the numeric entry: trillion (numeric definition).