Ethereum’s Fusaka upgrade to introduce transaction gas limit cap via EIP-7825

Ethereum’s highly anticipated hard fork Fusaka will activate with a major change to transaction gas limit cap.

The Ethereum Foundation said in a blog post on Tuesday, October 21, 2025 that Fusaka, the upcoming network upgrade, will feature an improvement proposal that sets the gas fee limit for each single transaction.

EIP-7825 will activate on the mainnet when Fusaka goes live, with rollout bringing a gas fee cap of 16.78 million gas per transaction.

According to EF, the limit is already live across the Holesky and Sepolia testnets.

Fusaka sees the changes activate on the Ethereum (ETH) mainnet.

“Previously, a single transaction could consume the entire block gas limit (~45 million gas), creating potential DoS risks and preventing parallel execution. EIP-7825 establishes a hard upper bound of 2²⁴ gas per transaction to improve block packing efficiency and pave the way for better parallel processing in future execution environments,” the EF wrote.

What does it mean for users?

While the gas fee cap limits the amount of gas each transaction can use, its application doesn’t impact overall block gas limit.

The cap also ensures that transaction blocks consist of several smaller and more predictable transactions – rather than one very large one.

As the change goes live on mainnet, one of the key things to note will be what developers and users relying on very large transactions should do.

Notably, the Ethereum Foundation advises that such users ensure their contracts and transaction builders align with the new cap.

“For most users, nothing changes. The vast majority of transactions are already well below 16 million gas,” Ethereum Foundation researcher Toni Wahrstätter said. “However, certain contracts and deployment scripts, particularly those performing batch operations, may exceed this limit. Such transactions will be invalid once Fusaka activates.”

When is Fusaka upgrade?

The Fusaka upgrade went live on the Sepolia testnet earlier this month, after activation in the Holesky testnet.

Activation on the mainnet is the next step in Ethereum’s push to further boost network scalability and performance.

Fusaka is expected to launch on the mainnet on December 3, 2025. Currently, the Sepolia deployment allows for stress testing of features such as the ones outlined via EIP-7825.