Adaptive Blocksize Limit Algorithm (ABLA)
bitcoin-cash · protocol · scaling
Bitcoin Cash consensus rules that adjust the maximum block size gradually in response to sustained block use.
The Adaptive Blocksize Limit Algorithm (ABLA) is the Bitcoin Cash consensus mechanism for setting each block's maximum size. Activated in May 2024, it replaced a single fixed ceiling with a limit that can respond to recent block utilization.
ABLA changes within bounded rates and retains a configured minimum, so one unusually large block cannot produce an abrupt increase. Sustained demand can raise the limit over time, while lower use can reduce an elevated limit toward the minimum.
ABLA governs permitted capacity, not actual demand, confirmation time, fees, or node performance. Larger blocks still require bandwidth, storage, propagation, and validation resources, so implementations and operators must monitor those costs.
May 2024 Bitcoin Cash network upgrade specification
The Bitcoin Cash scalability guide explains how adaptive capacity relates to node costs. The BCH upgrade history places ABLA alongside earlier and later changes.
Related terms
Block
→A batch of valid transactions added to a blockchain, linked to the previous block by a cryptographic hash.
mining · blockchain · security
Blockspace
→The limited transaction-data capacity available in a blockchain's blocks.
blockchain · economics · scaling
Consensus
→The process by which blockchain participants agree on valid transactions, blocks, and ledger history.
security · blockchain
Protocol Upgrade
→A coordinated change to the rules, messages, or policies implemented by network software.
governance · blockchain