Vitalik Says New Ethereum Rule Could Cut Confirmations To 12 Seconds

Vitalik Buterin says a new “fast confirmation rule” for Ethereum could give users a hard guarantee that a block will not be reverted after a single slot, or roughly 12 seconds, a change that would sharply reduce one of the network’s biggest practical frictions for exchanges, bridges and Layer-2 systems.

That distinction matters. Ethereum finality remains the chain’s strongest settlement guarantee, but it comes with a much longer wait time. Ma said the fast confirmation rule, or FCR, cuts deposit times from Ethereum mainnet to L2s and centralized exchanges to about 13 seconds, which he described as an “80-98% reduction for most L2s and exchanges.”

He added that the rule is expected to become “the new industry standard for L2s and exchanges,” and said it can begin rolling out in the coming months without a hard fork. That is a notable design choice. Rather than introducing a consensus change that requires network-wide coordination, FCR can be activated as clients implement it, with nodes able to run the rule automatically once support is live.

Ma’s explanation frames FCR as a middle ground between today’s heuristics and Ethereum’s formal finality. Most exchanges, L2s and solvers do not wait for finality now. Instead, they rely on a block-depth rule, or “k-deep,” essentially waiting for a transaction to be buried under enough subsequent blocks. FCR takes a different route: it counts attestations rather than blocks. According to Ma, that makes it structurally faster while also giving it a provable security model that k-deep lacks.

Even so, Ma argued the system degrades gracefully when conditions worsen. “If the network is slow, FCR has a built-in fallback mode. Instead of fast-confirming a block within 13 seconds, it may take slightly longer,” he wrote. “As soon as sufficiently many attestations are delivered, the block is fast-confirmed. In the worst-case, FCR falls back to finality.”

That fallback is central to the pitch. The mechanism does not pretend reorg risk disappears; it claims to reduce waiting time dramatically while retaining deterministic guarantees when its assumptions hold. Ma also stressed that if those assumptions do hold, a fast-confirmed block “will be finalized with certainty.”

At press time, ETH traded at $2,319.