# What is Gas? Whether it is the Ethereum network or other EVM-compatible networks, all operations on the blockchain need to consume Gas, just like a car needs to consume fuel. {% hint style="info" %} Gas Fee = Gas Price \* Gas Limit {% endhint %} ### Gas Price In the Ethereum Network, Gas Price can be set by the users. The unit for gas price is Gwei, 1 Gwei = 10^9 Wei. {% hint style="info" %} ETH, GWEI, WEI conversion: 1 ETH = 10^9 Gwei = 10^18 Wei {% endhint %} Gas Price is related to the transaction’s package speed. The higher the gas price you are willing to pay, the more incentivizing for miners to package your transaction on priority. ### Gas Limit Gas Limit is the maximum amount of gas a user can consume to conduct a transaction which is usually fixed at 21000 Gas. The Ethereum Yellowpaper pointed out that each transaction needs 21000 Gas, which is why the default gas limit setting in the Gas Fee page is 21000. If you need to change the gas fee, you can go to gas fee - customize - gas. However, it is recommended that you do not set the gas fee lower than 21000. ### How should I Select the Gas Fee when I Initiate a Transaction? In the gas fee page, O3 offers three gas fee options: "Fast", "Optimal", "Slow". You can select the gas fee option according to your own transfer needs. --- # 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.o3.app/guides/manage-your-crypto-assets/what-is-gas.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.