Definition
The block gas limit is a protocol-level metric that caps the total gas consumption of all transactions included in a single block. It defines how much computational work and storage modification a block’s transactions are collectively allowed to perform. On EVM-based networks, this limit constrains how many and what kind of transactions fit into a block, directly influencing network throughput and block execution characteristics.
Because each transaction specifies a gas amount and consumes gas as it executes, the sum of gas used by all transactions in a block must not exceed the block gas limit. This makes the block gas limit a key parameter for balancing performance, resource usage, and stability across blocks. It also serves as a safety boundary so that no single block can demand excessive computation from nodes in the network.
Context and Usage
In the context of a block, the block gas limit functions as a capacity constraint, similar to a maximum load that the block can carry in terms of gas. Miners or validators select transactions whose combined gas fits under this limit, which shapes how many complex smart contract interactions or simple transfers can be processed together. As a result, the block gas limit indirectly affects gas fee dynamics and the practical throughput of the chain.
Within the EVM environment, gas measures the cost of executing operations, and the block gas limit aggregates this cost at the block level. Networks may adjust this limit over time to reflect hardware capabilities and desired performance, but at any moment it remains a fixed upper bound for that block’s total gas usage. This metric is therefore central to understanding how blocks are structured, how block execution is constrained, and how overall system capacity is defined.