Mastering Ethereum, 2nd Edition

Chapter 2. Ethereum Basics

In this chapter, we will start exploring Ethereum. We’ll discuss how to use wallets, create transactions, and run a basic smart contract.

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, 1 ETH, Ξ1, or ♦1.

Tip

Use Unicode characters U+039E for Ξ and U+2666 for ♦.

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 as “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 1,000,000,000,000,000,000 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. Table 2-1 lists 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 seventh row.

Table 2-1. Ether denominations and unit names

Value (in wei)	Exponent ...