Gas is unit of measure on the [[Ethereum]] blockchain used to measure computational effort for transactions and [[Smart Contracts|smart contract]] execution on chain. It helps to prioritize transactions by assigning costs to smart contract operations using [[Opcodes|opcodes]] in the [[Ethereum Virtual Machine]]. Gas is also a key part of [[Transaction Fee Mechanisms|transaction fee mechanisms]]. To help with load balancing, a gas limit sets the maximum amount of gas allowed in a block. This ensures that blocks do not become too large, maintaining network efficiency, while gas fees provide an incentive for validators to prioritize and include transactions in blocks (based on the fees offered by users). Proposals such as [[Ethereum Proposals#^EIP-1559|EIP 1559]] direct the cost of adding a block to the chain and thus the ordering of transactions in said block. Note that this proposal was a key design change for Ethereum 2.0 and the transition to Proof of Stake. Because it includes a fee burn mechanism, gas fees are not paid directly to node operators. Validators on Ethereum 2.0 - unlike miners on Ethereum 1.0 - are not paid out the gas fees directly.