Ethereum's Sepolia testnet activated the Glamsterdam upgrade on October 6 at epoch 353,024 and began producing blocks with a gas limit of nearly 200 million, more than three times the 60 million cap allowed on the network's mainnet, according to an Ethereum Foundation announcement.

Gas is the unit that measures computing work on Ethereum, and the gas limit caps how much of that work can fit into a single block. The 200 million figure was scheduled in a commit for the Sepolia test network tied to epoch 353,024, a 6.4-minute time marker on Ethereum's calendar that began at 13:53:36 UTC.

Blocks have so far used only a fraction of the new room. An Etherscan snapshot of 25 consecutive Sepolia blocks taken on October 8, numbers 11,872,013 through 11,872,037, shows gas use ranging from 47.1 million to 85.9 million, roughly 24% to 43% of the limit. The snapshot covered the network's first days of operating under the new ceiling. Because Sepolia's activity comes from developers and test tooling rather than fee-paying demand, the occupancy figures describe the mechanics of the ceiling rather than conditions on mainnet.

A higher ceiling does not mean three times as many transactions. It only means a block can hold more when demand arrives. For everyday users, that headroom is what helps keep fees from spiking when many people use Ethereum at once, because congestion effectively amounts to strangers outbidding one another for space in the next block.

Bigger blocks are harder on validators, the operators who put up ETH as collateral to check and confirm each block. Ethereum Foundation researchers had warned that limits above 40 million could "fail to propagate as expected" across the network, so the limit has crept upward in small steps.

One of those steps was a 52%-to-48% validator vote in February 2025 that moved the limit from 30 million to 32 million. It was later raised to 60 million during 2025, double the original 30 million, and the Fusaka upgrade, which went live on December 3, 2025, made that figure the default.

Two changes on Ethereum's roadmap are intended to help the network handle more load. Block-level access lists record which accounts and data each block touches, so computers can check many transactions at once instead of one by one. Enshrined proposer-builder separation moves the auction that decides who assembles each block, today run through outside middleware, into Ethereum's own protocol rules.

Ethereum co-founder Vitalik Buterin sketched the longer arc in July, when he described a plan to replace almost every major piece of the protocol over three to four years. Glamsterdam is the nearer-term step, and Ethereum developers describe a possible gas-limit increase toward roughly 200 million after it.

Sepolia is a testnet, a practice network whose tokens carry no real value, so developers can break things without costing anyone money. The rollout follows Ethereum's standard sequence, in which upgrades pass through public testnets before a mainnet activation is scheduled. The activation also serves as a public check on the propagation questions raised around limits above 40 million. The same network staged the Merge rehearsal on July 6, 2022, when it switched to proof of stake ahead of the main network.

The announcement sets no date for Hoodi, Ethereum's other public testnet, and schedules no corresponding mainnet upgrade, so Ethereum's main network keeps its 60 million gas limit for now.