Wei refers to the smallest denomination of ether (ETH), the currency used on the Ethereum
network. For instance, 1 ether (ETH) is equivalent to 1x1018
wei (which may also be represented in exponential notation: 1e18 wei).
As the price of Ether and other cryptocurrencies
rises, the size of each blockchain
transaction tends to become smaller. For example, if ETH is priced at $10, one would need 10 ETH to make a $100 transfer. But if ETH is priced at $150, only 0.67 ETH would be sufficient to transfer the same value in USD. Using ether denomination may be troublesome as the transaction size becomes smaller.
In this context, wei and other denominations of ether may be useful for describing small value transactions, especially in regards to very small amounts of ETH that are typically used for transaction fees or when setting the gas limit of a transaction.
As presented on the Ethereum technical documents
, there are several other denominations of ether, each representing a multiple of wei. Gwei
and ether are among the most used denominations.
Similarly, Bitcoin uses the term satoshi to describe the smallest unit of its currency. 1 satoshi is equivalent to 0.00000001 BTC (or 10-8 BTC).
Although less popular, BNB has the term jager
to describe the smallest unit of BNB, where 1 Jager = 0.00000001 BNB (or 10-8