Solana cuts slot time to 200 milliseconds, final step set for around midnight KST Oct. 10

The target length of a slot, the basic unit in which Solana mainnet produces blocks, will drop from 250 milliseconds to 200 milliseconds around midnight KST on Oct. 10. Anza, the developer behind the Agave validator client, said on X on Oct. 7 that the 200 ms feature was pending activation on mainnet-beta, calling it the "Final slot reduction step." The change completes a plan that has trimmed the original 400 ms slot by 50 ms four times since August.

Anza said the feature activates in epoch 1052 and takes effect one epoch later, with 200 ms slots going live at the epoch 1053 boundary around 3 p.m. UTC on Oct. 9. An epoch is an operating cycle of 432,000 slots. On the afternoon of Oct. 9, mainnet was processing about 225 slots per minute, putting the actual slot length at about 267 ms.

Five block slots a second, each block smaller

At 200 ms, the network gets five chances to produce a block every second, double the rate at 400 ms, and twice as many blocks are produced per day. In exchange, the cap on how much computation a single block can hold, measured in compute units (CU), shrinks in line with slot time. According to the improvement proposal SIMD-0525, the per-block limit was 60 million CU at 400 ms and 37.5 million CU at 250 ms, and will be 30 million CU at 200 ms. Total capacity per unit of time stays the same, split into finer pieces.

The stretch in which a single validator produces consecutive blocks stays at four slots, so its real length falls from 1.6 seconds at 400 ms to 0.8 seconds. The proposal cites the shorter window a block-producing validator, or leader, has to delay, reorder or selectively include transactions as one reason for the cut. It also points to faster confirmation and finer timing for oracles and market-making programs that measure price freshness in slots. Epochs get shorter as well. According to the Solana Foundation's upgrade page, an epoch that lasted about 48 hours at 400 ms and about 30 hours at 250 ms will last about 24 hours at 200 ms.

Four 50 ms steps since August

SIMD-0525 was written on May 1 by Brennan Watt of Anza. Rather than cutting slot time in one go, it splits the change into four stages, 350 ms, 300 ms, 250 ms and 200 ms, each behind its own feature gate, so problems can surface at each step before the next. According to the foundation, mainnet moved to 350 ms on Aug. 21 (epoch 1020), 300 ms on Aug. 28 (epoch 1024) and 250 ms on Sept. 18 (epoch 1037). The 200 ms setting reached testnet and devnet first.

The foundation has said the network will not advance to the next step if block skip rates look too high. Actual slots have run slightly longer than target. Data from Solana Compass shows averages of 415 to 423 ms in the 400 ms era and 266 to 269 ms during the 250 ms stage (epochs 1037 to 1050).

Wallets get about 30 seconds to sign

The foundation said the change does not break existing programs, but anything that derives time from slot counts will shift. Code that multiplies slots by 400 ms will drift from real time, and the foundation advised reading the current slot duration or using the getBlockTime method instead of a hardcoded constant.

A recent blockhash included in a transaction remains valid for 150 blocks, as before. The block count is unchanged, but the wall-clock time has gone from about 60 seconds at 400 ms to about 38 seconds at 250 ms, and will be about 30 seconds at 200 ms. Transactions signed after a person reviews them, or signed offline, will have to move that much faster. Indexers that collect block data need no format changes but should prepare ingestion and storage for the higher block count. The foundation said ordinary users will see faster transaction confirmations.

SOL at about 150,000 won on Upbit, kimchi premium near 2%

At 5:30 p.m. KST on Oct. 9, SOL traded at 150,700 won on Upbit's Korean won market and also at 150,700 won on Bithumb. Binance quoted $110.10 at the same time, down 4.18% from 24 hours earlier. Converted to won, the Binance price was about 147,792 won, putting the kimchi premium (the gap between prices on Korean exchanges and global markets) at about 1.97% based on Upbit. SOL's 24-hour trading value on Upbit was about 55.4 billion won. Its 52-week high on Upbit was 314,900 won, set on Oct. 14, 2025.