Ether Currency Units

Ethereum’s currency unit is called ether, identified also as “ETH” or with the symbols Ξ (from the Greek letter “Xi” that looks like a stylized capital E) or, less often, ♦: for example, 1 ether, or 1 ETH, or Ξ1, or ♦1.

Ether is subdivided into smaller units, down to the smallest unit possible, which is named wei. One ether is 1 quintillion wei (1 * 1018 or 1,000,000,000,000,000,000). You may hear people refer to the currency “Ethereum” too, but this is a common beginner’s mistake. Ethereum is the system, ether is the currency.

The value of ether is always represented internally in Ethereum as an unsigned integer value denominated in wei. When you transact 1 ether, the transaction encodes 1000000000000000000 wei as the value.

Ether’s various denominations have both a scientific name using the International System of Units (SI) and a colloquial name that pays homage to many of the great minds of computing and cryptography.

Ether denominations and unit names shows the various units, their colloquial (common) names, and their SI names. In keeping with the internal representation of value, the table shows all denominations in wei (first row), with ether shown as 1018 wei in the 7th row.

Table 1. Ether denominations and unit names