# Gas Fee Gas refers to the amount of computational work required to perform a specific operation on the Ethereum network. Since each Ethereum transaction requires computational resources to execute, each transaction requires a fee. By requiring a fee for every computation executed on the blockchain, bad actors can be prevented from spamming the network. The fundamental unit of computation is "gas". Gas limit refers to the maximum amount of gas you are willing to consume on a transaction. More complicated transactions involving smart contracts require more computational work, so they require a higher gas limit than a simple payment. Although a transaction includes a limit, any gas not used in a transaction is returned to the user (i.e. max fee - (base fee + tip) is returned). On Zecrey L1 and Legend wallet(the NFT-oriented L2 solution of BNB chain), the native token of the blockchain will be used as the gas token. On Zero wallet, users can choose any supported token as gas fee in the transaction. --- # Agent Instructions: Querying This Documentation If you need additional information that is not directly available in this page, you can query the documentation dynamically by asking a question. Perform an HTTP GET request on the current page URL with the `ask` query parameter: ``` GET https://docs.zecrey.com/education/concepts-explained/crypto-knowledge/gas-fee.md?ask= ``` The question should be specific, self-contained, and written in natural language. The response will contain a direct answer to the question and relevant excerpts and sources from the documentation. Use this mechanism when the answer is not explicitly present in the current page, you need clarification or additional context, or you want to retrieve related documentation sections.