Ethereum's Fusaka hard fork activated on 4 December 2025, marking the network's second major upgrade of the year. The upgrade increased the block gas limit to 60 million and introduced Peer Data Availability Sampling (PeerDAS), a technical improvement designed to reduce the cost and increase the throughput of Layer-2 rollups. For everyday ETH users, Fusaka's practical effect is lower transaction fees on Layer-2 networks.

What Fusaka changed: the two core improvements

1. Block gas limit increase to 60 million

The block gas limit determines how many transactions Ethereum can process per block. Fusaka raised this limit from approximately 36 million to 60 million gas — an increase of around 67%. This allows more transactions to be included in each block, increasing base-layer throughput.

2. PeerDAS — Peer Data Availability Sampling

PeerDAS is a data availability mechanism that allows Ethereum nodes to verify that data posted by Layer-2 rollups is available — without each node needing to download the entire dataset. According to Ethereum Foundation documentation, PeerDAS is designed to increase data throughput for Layer-2 rollups by up to 8x.

The practical result: Layer-2 networks built on Ethereum — including Arbitrum, Optimism, Base and others — can post more data to the Ethereum base layer at lower cost, which directly reduces user-facing transaction fees on those networks.

Key facts: Fusaka upgrade

• Activation date: 4 December 2025

• Block gas limit: increased from approximately 36 million to 60 million gas

• PeerDAS: designed to boost Layer-2 data throughput by up to 8x

• Impact on Layer-2 fees: significant reduction in data posting costs for rollups

• Fusaka is Ethereum's second major upgrade of 2025, following Pectra in the first half of the year

• Charles Schwab announced plans to launch direct ETH trading for US clients in H1 2026, citing Fusaka's scalability improvements (April 2026)

What Fusaka means for different users

For users of Layer-2 networks such as Arbitrum, Optimism, Base or zkSync, Fusaka's primary benefit is lower transaction costs. Layer-2 networks periodically post compressed transaction data — called blobs — to the Ethereum base layer. By reducing the cost of blob storage, Fusaka makes these posts cheaper, and those savings are passed on to users.

For holders of ETH itself, Fusaka introduces a nuanced dynamic. The upgrade reduces data posting costs, which tends to decrease the amount of ETH burned per transaction. Short-seller Culper Research published a report in April 2026 arguing that Fusaka had weakened ETH tokenomics by reducing fee revenue and enabling higher transaction volumes at lower cost per transaction.

What comes next for Ethereum in 2026

The Ethereum roadmap extends well beyond Fusaka. Two additional scalability upgrades are planned for 2026. The longer-term 'Ethereum roadmap north stars' outline goals including near-instant transaction finality, Layer-1 throughput of approximately 10,000 TPS, post-quantum cryptography and native privacy features — though these are research targets, not committed timelines.

Frequently Asked Questions

What is the difference between Fusaka and the Pectra upgrade?

Both were 2025 Ethereum hard forks. Pectra, which activated in the first half of 2025, focused primarily on validator experience and staking improvements. Fusaka focused on scalability — increasing the block gas limit and introducing PeerDAS for Layer-2 data availability.

Do I need to do anything as an ETH holder after Fusaka?

No. Ethereum hard forks do not require ETH holders to take any action. If you store ETH in a self-custody wallet or on a platform that supported the upgrade, your funds are unaffected.

Did Fusaka create a new ETH token?

No. Fusaka is a protocol upgrade, not a fork that creates a new token. The existing ETH continues as the sole native asset of the Ethereum network.

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This article is for informational purposes only and does not constitute financial advice, investment guidance or a recommendation to buy, sell or hold any digital asset. Cryptocurrency involves risk. Always conduct your own research before making financial decisions.