What it is
Gwei is a denomination of Ether (ETH), where one Gwei equals 0.000000001 ETH, or one billionth of an Ether. It is the standard unit for measuring gas fees on the Ethereum network. The term "Gwei" is a portmanteau of "giga" (a prefix meaning a billion) and "Wei" (the smallest unit of Ether). Using Gwei makes it easier to express small transaction costs without dealing with many decimal places.
When users interact with the Ethereum network, they specify the gas price they are willing to pay per unit of gas, typically expressed in Gwei. For example, if a transaction costs 21,000 gas and the gas price is 20 Gwei, the total fee is 420,000 Gwei (0.00042 ETH). Retail investors check current Gwei prices using block explorers or wallet interfaces to estimate their transaction costs and avoid overpaying.
Why it matters
Gwei is the standard unit for gas fees, helping you accurately estimate and manage your Ethereum transaction costs.
Reviewed under editorial standardsUpdated September 26, 2026Not investment advice