Gwei is a unit of measurement for the gas price in the Ethereum network, representing a very small amount of ether (ETH). It is equivalent to one billionth of an ETH. Gas is the fee paid by users to execute a transaction or smart contract on the Ethereum network. The gas fee is calculated as the gas price (in Gwei) multiplied by the amount of gas required to execute the transaction. The Gwei price is denominated in ETH, and it can vary depending on network congestion and demand. Gwei is used to help calculate the Ethereum blockchain's transaction charges, which are typically much lower to USD than ETH itself.