Ethereum's Sepolia testnet activated the Glamsterdam upgrade on October 6, introducing a block gas limit of nearly 200 million, more than three times the 60 million limit on Ethereum's main network. The upgrade took effect at epoch 353,024, a designated time marker in Ethereum's calendar.
Gas measures computing work on Ethereum, and the gas limit determines how much work can fit into a single block. Despite the significantly higher limit, early block data shows restraint in usage. A sample of 25 consecutive blocks recorded on October 8 (blocks 11,872,013 through 11,872,037) showed gas consumption ranging from roughly 24% to 43% of the available limit.
A higher gas limit does not directly translate to proportionally more transactions, but rather provides additional capacity when network demand increases. The expanded headroom is designed to help prevent transaction fees from spiking during periods of high congestion, when users compete to include their transactions in the next block.
Larger blocks create operational challenges for validators, the network participants who stake ETH as collateral to verify and confirm transactions. Ethereum Foundation researchers have cautioned that limits exceeding 40 million could face propagation issues across the network, leading to gradual increases rather than dramatic jumps.
The testnet's gas limit follows incremental upgrades on the main network. A validator vote in February 2025 moved the limit from 30 million to 32 million. The limit later increased to 60 million during 2025, and the Fusaka upgrade, which went live on December 3, 2025, made that the new standard.
Ethereum's roadmap includes other measures to increase network capacity. Block-level access lists would allow validators to check multiple transactions simultaneously rather than sequentially, while enshrined proposer-builder separation would move transaction-ordering auctions into Ethereum's core protocol rules, currently handled through external systems.
The announcement includes no timeline for testing on Hoodi, another public testnet, and schedules no upgrade to the main network, leaving Ethereum's current gas limit at 60 million.
