Ethereum gas: why failed calls still cost

Gas measures execution work. It is not the amount being transferred. A contract call can send no ETH to a recipient while still consuming gas, because nodes performed computation.

A failed reservation

Suppose a contract checks whether a ticket is available, then rejects the reservation. Reverting the call undoes its application state changes. It does not undo the work spent executing the checks, so an included, failed transaction can still incur a fee.

The execution fee depends on gas used multiplied by the price per unit of gas. A gas limit bounds permitted work; it is not a guarantee that the call will succeed. Ethereum fees include a protocol base fee and a priority fee. Applications must estimate both the required work and the fee settings instead of confusing a token transfer's amount with its execution budget.

When comparing Circle Arc's USDC gas, ask which asset pays for execution and how fees are calculated. A familiar EVM call does not imply the same fee asset or fee policy.

Sources and further reading