What Is Gwei?
A gwei is a unit of Ether, the cryptocurrency used on the Ethereum network. The name is short for "giga-wei." One gwei equals one billionth of an Ether, or 10^-9 ETH. The smallest unit on the network is the wei, and one gwei is exactly one billion wei.
Why Gwei Is Used
Transaction costs on Ethereum are usually small fractions of a whole coin. Writing those amounts in gwei keeps them as readable numbers rather than long strings of decimal zeros. Gwei appears most often in gas fees, which are the transaction fees users pay to have their operations processed by the network. Gas prices are quoted in gwei per unit of gas, and the total fee is calculated as follows:
Total fee (in ETH) = gas used × gas price (in gwei) ÷ 1,000,000,000
How Gas Prices Change
Gas prices rise and fall with demand for block space. When many users submit transactions at once, each block fills up, and users bid higher prices to be included sooner. When demand is low, prices fall. Because the market works through bidding, the same operation can cost very different amounts at different times.
Why It Matters to Investors
Gwei is a unit of measurement, not a measure of value. Investors who use Ethereum may notice gas costs when moving or trading Ether, and changes in gas prices can affect the cost of using applications built on the network. Understanding the unit helps when reading fee figures in wallets and blockchain explorers. Because gas levels change constantly, any specific gwei figure reflects network conditions at one moment only.
Updated November 5, 2026. For general education only; not financial, tax or legal advice.