Gas fee (network fee)

Gas is the fee you pay to have a transaction processed on a blockchain. On Ethereum, every operation consumes a measured amount of "gas", and you pay for it in ETH at a price per unit quoted in gwei (one billionth of an ETH). Complex actions such as swaps cost more gas than a simple transfer.

Since the London upgrade in August 2021 (EIP-1559), each Ethereum block has a base fee that is burned and rises or falls with demand, plus an optional tip to validators. On Bitcoin, fees are quoted in satoshis per virtual byte and depend on the transaction's size in data, not the amount sent.

Fees rise when the network is busy. Layer-2 networks and less congested chains offer much cheaper transactions. A failed transaction on Ethereum still costs the gas it used.