Gwei is a unit of Ether (ETH)Ether (ETH)The currency of the Ethereum network, used to pay network fees, as a stake under proof of stake and to send value between people., the currency of the Ethereum network. One gwei is one billionth of an ETH, or 0.000000001 ETH. Gwei is used to quote the price of GasGasThe unit that measures the computing work a transaction or smart contract needs on Ethereum, which sets how high the network fee is., and therefore network feesNetwork feeA fee paid to a crypto network, not to a bank or company, for including your transaction in a block. on Ethereum, because the amounts are so small that writing them in ETH would be awkward.
The units of ether
The smallest unit of ether is the wei. The name is usually traced to the computer scientist Wei Dai, who described an idea called b-money in 1998, a decade before Bitcoin appeared. The name gwei stands for gigawei, a billion wei.
| Unit | In wei | In ETH |
|---|---|---|
| Wei | 1 | 0.000000000000000001 |
| Gwei | 1,000,000,000 | 0.000000001 |
| Ether | 1,000,000,000,000,000,000 | 1 |
This is similar to the Satoshi (sats)Satoshi (sats)The smallest unit of bitcoin: one satoshi is one hundred-millionth of a bitcoin, or 0.00000001 BTC., the smallest unit of bitcoin. The difference is that a bitcoin divides into 100 million satoshis, while one ETH divides into a billion billion wei.
An example
A simple ETH transfer uses 21,000 units of gas. If the base fee and priority fee add up to 5 gwei per unit, the transfer costs 21,000 × 5 = 105,000 gwei, or 0.000105 ETH. If one ETH cost ISK 500,000, that would be about ISK 52.
Gas prices change with demand. In quiet periods they have dropped below 1 gwei, while at the busiest times they have reached hundreds of gwei.
Why does it matter?
Wallets often show the gas price in gwei before you confirm a transaction. If you know what a gwei is, you can tell whether the fee is normal or unusually high, and decide to wait if the network is busy. The fee is split into a base fee and a priority feeBase fee and priority feeThe two parts of a transaction fee on Ethereum. The network sets the base fee, which is burned, while the priority fee goes to the validator., which you can read more about in that entry.
Everything in Myntkaup Learn is written and regularly reviewed by the Myntkaup editorial team. It is for education and is not investment advice. Editorial policy. Updated 2 November 2026.