Ethereum Blob limit increased to 21: Layer 2 throughput upgraded again, expansion roadmap accelerates progress

The Ethereum network has recently undergone an important upgrade. On Wednesday, Ethereum completed its second hard fork that only adjusts the Blob parameters (BPO), officially increasing the maximum number of Blobs per block from 15 to 21, which is regarded as a key first step in Ethereum’s 2026 scalability roadmap. This upgrade directly enhances the data throughput capacity of the Ethereum Rollup system, laying the foundation for Layer 2 scaling.

The BPO hard fork took effect at 1:01:11 UTC. The core change not only involves increasing the Blob limit but also raising the Blob target count from 10 to 14. Industry consensus generally considers the target number more practically meaningful than the theoretical maximum, as approaching the 21 Blob limit over the long term could put pressure on node bandwidth and storage capacity.

In terms of data capacity, one Blob unit can hold approximately 128KB of data, meaning a single Ethereum block can now carry up to about 2688KB of Rollup data. This significantly improves the batch processing capability of the Ethereum Layer 2 network, helps reduce Rollup costs, and supports higher-frequency on-chain activities.

The Blob mechanism not only serves scalability but also contributes to the stability of the mainnet. As more transactions are transferred to Rollup execution, congestion on the Ethereum mainnet decreases. Data shows that since the first BPO hard fork implementation on December 9, 2025, Ethereum Gas fees have generally stabilized, indicating that the Blob mechanism is playing a “buffer” role.

Meanwhile, the developer community has begun discussing further plans to increase Ethereum’s throughput. At the core developer meeting in mid-December, a proposal was made to raise the network Gas cap from the current 60 million to 80 million after the second BPO upgrade. If implemented, the number of transactions and smart contracts executable per block would significantly increase, further improving user experience and reducing average transaction fees.

Looking further ahead, the Glamsterdam hard fork planned for late 2026 is expected to push scalability to a new stage. This upgrade will raise the Gas cap to 200 million and introduce a “perfect parallel processing” mechanism. Through the EIP-7928 block access list design, Ethereum aims to shift from a single-threaded transaction processing mode to multi-threaded parallel execution, greatly increasing overall transaction throughput.

Overall, from increasing the Blob limit, to discussing Gas cap upgrades, and then to the Glamsterdam hard fork, Ethereum is systematically advancing its scalability upgrades. This technical path centered on Rollup, Blob, and parallel execution is gradually transforming Ethereum into a global settlement and execution network capable of supporting large-scale applications.