Fastest L2 block time, live across Arbitrum, Base, Optimism and 6 more
Wall-clock interval in milliseconds between two consecutive newHeads events on each L2 sequencer, refreshed continuously.
This benchmark measures the live block time of every major Ethereum Layer 2, the actual wall-clock interval between two consecutive newHeads events on the sequencer, not the marketing figure each chain advertises. Arbitrum One leads with sub-second blocks (~250 ms median), built on Nitro's fast-finality fork. Optimism, Base, Blast and Mantle all cluster around the 2 s OP Stack default. zkSync Era, Linea and Scroll show batched cadence with p50 around 3-6 s and a long tail on idle gaps. Taiko's based rollup sits at the 3 s mark. The p99 column reveals stalls 2-3× the nominal block time on every L2, the part marketing pages never quote.
Methodology
We measure the live block time of every major Ethereum L2 by holding a persistent WebSocket subscription to `eth_subscribe("newHeads")` on each sequencer. The harness records T1 when block N arrives and T2 when block N+1 arrives; the sample is wall-clock T2 − T1 in milliseconds. p50 / p90 / p99 are computed via Prometheus `quantile_over_time` over the 24 h window. The histogram bucket boundaries (50 ms → 60 s) cover the full range from Arbitrum's sub-second cadence to zk-rollup batching gaps. Disconnects reconnect with exponential backoff and the natural outlier sample is capped at 5 min so a reconnect can't pollute p50.
Block time by chain
Live p50 over the last 24 hours, ranked lowest first. Each chain has its own consensus mechanism. The explainer below matches what the harness actually measures.
Arbitrum One block time
285 ms p50 over the last 24 hours · Nitro fast-finality, sub-second sequencer.
Arbitrum One block time is 285 ms (p50, 24h). Arbitrum Nitro defaults to a 250 ms sequencer interval, by far the most aggressive cadence in the L2 cohort, made possible because the Nitro stack decouples block production from L1 anchoring and runs a single Offchain Labs sequencer that posts batches to Ethereum asynchronously. Measured by holding an `eth_subscribe("newHeads")` WebSocket on the public Arbitrum RPC and recording wall-clock deltas between consecutive head events.
zkSync Era block time
1.66 s p50 over the last 24 hours · zk-rollup, batched producer.
zkSync Era block time is 1.66 s (p50, 24h). zkSync Era is a zk-rollup with a Matter Labs-operated sequencer; block production is batched because the prover must generate a SNARK before the batch is finalized on Ethereum, so within a busy burst blocks land near 1 s but the median drifts up during quiet periods when the sequencer waits to fill a batch. Measured via the `era.zksync.io/ws` WebSocket and `newHeads` inter-arrival deltas.
Mantle block time
1.80 s p50 over the last 24 hours · OP Stack fork, modular DA, 2 s sequencer.
Mantle block time is 1.80 s (p50, 24h). Mantle is an OP Stack fork with a Mantle Foundation sequencer at the OP Stack 2 s default, but it swaps Ethereum calldata for EigenDA as the data-availability layer, which decouples DA cost from L1 blob price without changing the L2 block cadence the user sees. Measured via `newHeads` inter-arrival on the public Mantle sequencer WebSocket.
Optimism block time
1.95 s p50 over the last 24 hours · OP Stack default, 2 s sequencer.
Optimism block time is 1.95 s (p50, 24h). The OP Stack ships with a hard-coded 2 second sequencer interval, which is what the Optimism Foundation sequencer commits to; the L2 only produces a new block when that timer fires, even on empty traffic. Settlement is on Ethereum via blob calldata after Dencun. Measured by holding a persistent `newHeads` WebSocket against the public Optimism sequencer RPC and reporting the inter-arrival delta.
Taiko block time
1.99 s p50 over the last 24 hours · Based rollup, L1-sequenced by Ethereum validators.
Taiko block time is 1.99 s (p50, 24h). Taiko is a based rollup: there is no centralized sequencer; Ethereum L1 validators sequence Taiko blocks directly by including L2 proposals in L1 blocks, which means Taiko's effective slot is bounded below by Ethereum's 12 s slot. The architecture trades raw L2 cadence for inheriting Ethereum's liveness and censorship-resistance. Measured via `newHeads` on the public Taiko WebSocket.
Blast block time
1.99 s p50 over the last 24 hours · OP Stack fork, 2 s sequencer + native yield.
Blast block time is 1.99 s (p50, 24h). Blast is an OP Stack fork operated by the Blast team with the same 2 s sequencer default as Optimism and Base, layered with native yield on ETH and USDB deposits that auto-rebase against L1 staking and T-bill yields. Settlement is on Ethereum via blob calldata. Measured live by holding a `newHeads` WebSocket against the Blast sequencer RPC.
Base block time
2.03 s p50 over the last 24 hours · OP Stack, 2 s sequencer.
Base block time is 2.03 s (p50, 24h). Base is operated by Coinbase on the OP Stack and inherits its 2 second sequencer cadence; Coinbase has publicly tested a Flashblocks pre-confirmation path at 200 ms but the canonical `newHeads` stream still emits one block every 2 s. Settlement posts to Ethereum via EIP-4844 blobs. Measured live by subscribing to `newHeads` on the public Base sequencer WebSocket and computing T(N+1) minus T(N) in milliseconds.
Scroll block time
4.25 s p50 over the last 24 hours · zkEVM rollup, prover-bound cadence.
Scroll block time is 4.25 s (p50, 24h). Scroll is a bytecode-equivalent zkEVM running a centralized sequencer that batches transactions for a Halo2-based prover; the nominal block target is 3 s but the practical floor is driven by the prover-batch cadence, identical in shape to Linea and zkSync, with a long idle tail when traffic is sparse. Measured via the public Scroll WebSocket and `newHeads` deltas.
Linea block time
5.59 s p50 over the last 24 hours · zk-rollup, prover-bound cadence.
Linea block time is 5.59 s (p50, 24h). Linea is a Consensys-operated zkEVM with a single sequencer feeding a prover that produces PLONK-family proofs posted to Ethereum; the documented target is a 2 s slot but observed cadence is governed by prover throughput, so idle windows stretch into multi-second gaps that lift the median above the nominal slot time. Measured by holding `newHeads` on the public Linea RPC.
Frequently asked
What is the fastest Layer 2 block time?
Arbitrum One leads the leaderboard at sub-second block times, typically 200-300 ms median, occasionally spiking past 800 ms under load. Arbitrum Nitro's fast-finality fork is the reason: it commits blocks every 250 ms by default, far below the 2 s convention used by most OP Stack chains.
Why are Base and Optimism block times so similar?
Base and Optimism both run the OP Stack with the same default sequencer cadence (2 s). Blast and Mantle are also OP Stack forks, their block times cluster identically. The architectural similarity is by design: OP Stack is meant to be a turnkey rollup framework where the sequencer interval is a configuration constant, not a chain-specific design choice.
What is the block time on zkSync Era, Linea, and Scroll?
zk rollups produce blocks in bursts rather than at a fixed cadence. p50 sits around 3-6 s but p90 / p99 can balloon to 15-30 s during idle periods because the sequencer waits for enough transactions to fill a batch before generating the validity proof. The nominal '2 s block time' those chains advertise is the within-burst figure, not the median observed externally.
Is L2 block time the same as L2 finality?
No. Block time measures how often the sequencer produces a block, it's a soft confirmation, reversible if the sequencer decides to. Finality on an L2 means the L1 anchor batch is final on Ethereum, which takes 12-18 minutes (block posting + 12.8 min Casper finality) at best, and 7 days for optimistic rollups under contestation. We track the latter in a separate bench.
How is the L2 block time measured here?
We hold one persistent WebSocket subscription per L2 via `eth_subscribe('newHeads')`. Every new head event is timestamped on receipt and the difference between consecutive events is the block-time sample. p50 / p90 / p99 are computed via Prometheus `quantile_over_time` over the last 24 h. Reconnect artifacts above 5 min are filtered so a network blip can't skew the percentiles.
What about Polygon zkEVM, Mode, Starknet and the rest?
Polygon zkEVM and Mode don't expose a public WebSocket endpoint without an API key, so we defer them to v2 when an API-keyed contributor endpoint lands. Starknet uses the Cairo stack with a different RPC shape, it would live in a dedicated bench rather than be shoehorned into the EVM cohort here. Berachain, Sonic and other adjacent chains are L1s, not L2s, so they live in the l1-finality bench.
Source code github.com/ChainBench/OpenChainBench/tree/main/harnesses/l2-block-time