Block Capacity

Overview

Block capacity limits how much work the network processes in one block. Bitcoin uses block weight, which accounts differently for witness and non-witness data. Ethereum execution blocks use a gas limit, while blob transactions also consume separate blob capacity.

Capacity is a security and decentralization parameter. Larger blocks can increase throughput, but they take longer to propagate and require more bandwidth, storage, and computation from nodes. If resource requirements become too high, fewer participants may be able to validate the chain independently.

When demand exceeds capacity, transactions compete for inclusion. Fee markets then prioritize transactions according to protocol and producer policies. This can increase payment costs and confirmation delays during congestion.

Capacity should not be confused with actual block usage. A block can be below its maximum. Nor does more capacity automatically mean more final throughput, because execution complexity, state growth, propagation, and consensus constraints also matter.

Capacity changes influence both throughput and decentralization. Raising limits can let the network process more data or computation per block, but it also increases propagation time, storage growth, bandwidth use, and validation cost. Higher requirements can make it harder for ordinary participants to operate nodes.

When demand approaches the limit, users compete through fees, and low-fee transactions may wait longer. Scaling systems reduce pressure by batching activity or executing it elsewhere, but they still rely on some base-layer resource for settlement or data availability. Capacity should therefore be evaluated with block frequency, transaction complexity, node requirements, and fee-market design rather than quoted as one universal transactions-per-second number.