Fusaka Update – Transaction Gas Limit Cap arrives with EIP-7825

Starting with the upcoming Fusaka hard fork, EIP-7825 introduces a per-transaction gas limit cap of 2²⁴ (≈ 16.78 million gas).

This change is already live on Holesky and Sepolia, and will activate on mainnet with Fusaka.

Developers and users who rely on very large transactions should verify that their contracts and transaction builders conform to the new cap.

Background

As Ethereum scales to higher block gas limits and prepares for parallel execution (e.g. EIP-7928 in Glamsterdam), the Fusaka fork introduces a per-transaction gas limit cap.

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.

This cap does not affect the overall block gas limit but only restricts how much gas a single transaction may use. In practice, this ensures that blocks consist of multiple smaller, more predictable transactions instead of one very large one.

Impact

For most users, nothing changes. The vast majority of transactions are already well below 16 million gas [0].

However, certain contracts and deployment scripts, particularly those performing batch operations, may exceed this limit. Such transactions will be invalid once Fusaka activates.

If you maintain infrastructure that generates transactions close to the previous block gas limit, you should:

1. Simulate transactions against Holesky or Sepolia, both of which already enforce the 2²⁴ cap.
2. Refactor batch operations into smaller, sequential transactions if needed.
3. Pre-signed transactions may need to be re-signed using a lower gas limit if the transaction’s gas limit exceeds the new limit.
4. Verify tooling, especially contract deployers, routers, and batching scripts, to ensure gas usage remains below the new cap.

See [1] for an empirical impact analysis.

The new transaction gas limit cap does not affect the limits for eth_call.

Actionable Changes

• Test deployments and transaction builders on Sepolia or Holesky.
• Adjust any gas estimation logic that assumes a higher per-transaction limit.
• Update monitoring and alerting systems to flag transactions above the new gas limit.

All major client implementations (Geth, Erigon, Reth, Nethermind, Besu) have included this change in their Fusaka-ready releases.

Outlook

The per-transaction gas limit cap is part of Ethereum’s ongoing transition toward parallel execution. While it may require adjustments, it establishes a safer and more predictable foundation for higher throughput in future forks.

Developers and ecosystem teams are encouraged to test on public testnets before mainnet activation and to follow discussions in AllCoreDevs and Ethereum Magicians for upcoming EIPs.

The full discussion and rationale for the gas limit introduced in EIP-7825 can be found in [2].

A PEEPanEIP episode with Giulio from Erigon can be found in [3].

References

[0] https://github.com/nerolation/EIPs/blob/17a90c395dd48099d5bcb740be1a76249cdad996/assets/eip-7825/analysis.md

[1] https://github.com/nerolation/EIPs/blob/17a90c395dd48099d5bcb740be1a76249cdad996/assets/eip-7825/analysis.md

[2] https://ethereum-magicians.org/t/eip-7987-transaction-gas-limit-cap-at-2-24/24746

[3] https://www.youtube.com/watch?v=qg4FX4aCsRc