What does sextillion mean?
A sextillion is an exceptionally large cardinal number whose value depends on the scale system in use. Under the short scale now standard in the United States and widely used internationally, a sextillion equals 10^21, or 1 followed by 21 zeros. It is the sixth successive unit obtained by multiplying by 1,000 and is 1,000 times a quintillion. Traditional British long-scale usage instead assigned the term to 10^36, a vastly larger value. Consequently, the word appears chiefly in mathematics, science, economics, and speculative contexts in which very large quantities are compared. Although modern readers are most likely to understand the short-scale value, the term remains notable because older British texts can use the same word for a different number. “Sextillion dollars” is a familiar rhetorical expression for an almost unimaginable sum, while formal mathematical writing often prefers an unambiguous power-of-ten notation.
nounA cardinal number equal to one million million million million million million (10^21) in the short scale used in the United States and most contemporary contexts. In the traditional British long scale, it denotes 10^36.
- In the short scale, a cardinal number equal to 10^21.
- In the traditional British long scale, a cardinal number equal to 10^36.
"The project is expected to cost more than a sextillion dollars over its lifetime."
"Even the smallest unit of the hypothetical material would carry a price measured in sextillions of credits."
"The scale was especially important in nineteenth-century British scientific writing, where it denoted 10^36."
The plural is used when the number itself is being treated as countable, although scientific and financial contexts often favor the numerical notation.
"Astronomers debated whether there could be sextillions of inhabited planets in the observable universe."
In the US short scale, sextillion is the “21-zeros” number: 1,000,000,000,000,000,000,000.
Reviewed by Deb Chak, Editor. AI-assisted content curated by RJS Tech Solutions LLP.
Where does sextillion come from?
The word entered English in the early 18th century from New Latin sextillion, a formation based on Latin sextus, meaning “sixth.” It was associated with the system that named successive powers of a thousand by the corresponding ordinal numbers. This original short-scale sense was later followed by a different long-scale value in traditional British usage.
Related word forms
How sextillion is actually used
Modern US usage generally follows the short scale, making the word equal to 10^21. Traditional British usage followed the long scale, in which it represented 10^36, so the numerical value depends on the naming convention and historical context.
Easily confused with sextillion
A quintillion is 10^18 in the short scale, whereas a sextillion is 10^21 and is therefore a thousand times larger.