Ethereum’s currency unit is called ether and is subdivided into smaller units, down to the smallest unit possible which is named wei. One ether is 1 quintilion wei (1 x 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 mistake.
The value of ether is always represented internally in Ethereum as integer multiples of wei. When you transact 1 ether, the transaction encodes 1018 wei as the value.
Ether’s various denominations have a 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 cryptography and computer science.
Table Ether Denominations and Unit Names shows the various units, their colloquial (common) name and their SI name. 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:
| Value (in wei) | Exponent | Common Name | SI Name |
|---|---|---|---|
1 |
1 |
wei |
wei |
1,000 |
103 |
babbage |
kilowei or femtoether |
1,000,000 |
106 |
lovelace |
megawei or picoether |
1,000,000,000 |
109 |
shannon |
gigawei or nanoether |
1,000,000,000,000 |
1012 |
szabo |
microether or micro |
1,000,000,000,000,000 |
1015 |
finney |
milliether or milli |
1,000,000,000,000,000,000 |
1018 |
ether |
ether |
1,000,000,000,000,000,000,000 |
1021 |
grand |
kiloether |
1,000,000,000,000,000,000,000,000 |
1024 |
megaether |
Compare to bitcoin: single input, single output.
Source /Destination ………. EOA ……… contract
EOA …….. X ………. Y
Contract….. Z ……….. Q
Four types?
One type, four combinations
Source, dest, signature, amount, gas limit, gas price, nonce, data
Tx is simpler than bitcoin, complexity is at a higher level (EVM)