Gas and fees | ethereum.org
Gas fees have to be paid in Ethereum's native currency, ether (ETH). Gas prices are usually quoted in gwei, which is a denomination of ETH. Each gwei is equal to one-billionth of an ETH (0.000000001 ETH or 10 -9 ETH). For example, instead of saying that your gas costs 0.000000001 ether, you can say your gas costs 1 gwei.