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Ethereum bumps blob capacity as it gears for Fusaka upgrade

Ethereum increased its data capacity per block, raising the blob target to 14 and the maximum blob limit to 21.

Updated Jan 8, 2026, 12:56 p.m. Published Jan 8, 2026, 4:21 a.m.
Ethereum's new "blob market" is taking on a life of its own. (Wikipedia/PhotoMosh)

What to know:

  • Ethereum increased its data capacity per block, raising the blob target to 14 and the maximum blob limit to 21.
  • This change is part of Ethereum's strategy to scale by enhancing data availability rather than relying on major network overhauls.
  • The update aims to stabilize rollup fees and ensure smoother transactions as rollup activity grows.

Ethereum raised the amount of data it can carry per block on Tuesday, a small but important change for the network’s rollup-heavy scaling path.

The update increased the blob target to 14 from 10 and lifted the maximum blob limit to 21 from 15. Blobs are the data packets rollups publish to Ethereum so they can settle transactions cheaply offchain while still relying on Ethereum for security and finality.

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The move came through Ethereum’s second blob parameter-only fork, part of a broader plan to scale by steadily widening data availability rather than relying on infrequent, headline upgrades.

Blobs matter because they are now one of the main cost drivers for layer-2 networks like Base, Arbitrum, Optimism, and Mantle, as well as zero-knowledge rollups such as zkSync Era, StarkNet, and Scroll.

When blob space is scarce, rollup fees can spike. When blob space expands, rollups get more breathing room and users see more stable costs.

For now, demand is not close to breaking the system.

On-chain data shows blob usage remains well below capacity even as rollup activity continues to rise. That suggests Ethereum has meaningful headroom in its data layer today and is preemptively scaling, before congestion forces the issue.

The shift also reinforces a broader change in Ethereum’s roadmap. Instead of treating scaling as a sequence of major forks that overhaul the network, Ethereum is increasingly tuning the knobs around data availability and throughput in smaller steps, then iterating.

That approach aligns with Ethereum co-founder Vitalik Buterin’s earlier this week that the network is entering a new phase, where upgrades like data availability sampling and progress on zkEVM can push Ethereum toward higher bandwidth without sacrificing decentralization.

The latest blob increase is not a market-moving event on its own. But it signals how Ethereum intends to scale from here: gradually, predictably and with rollups as the primary consumer of blockspace.