What is block height?

Ethereum started at block 0 in July 2015, and since the Merge it adds one block per 12-second slot, minus the odd missed slot.

Solana is a little different. Its clock is the slot, a window of about 400 milliseconds in which one leader may produce a block. When a leader misses its turn the slot is skipped, so the Solana slot number runs ahead of the block height. Both keep rising. People mix them up all the time.

The number matters most when it stops moving. If the height an RPC reports stays flat, either the chain has halted or that endpoint has fallen behind, and the second is far more common. Block age, the time since the newest block, turns this into something you can read at a glance. A few seconds is normal. Minutes means trouble.

Imagine the Base height on your screen has not changed for 90 seconds. Base seals a block every two seconds, so about 45 blocks are missing. Before you decide Base is down, check a second endpoint. A stuck RPC connection is the likelier story.

Also called: block number, slot height.

The Chain status widget shows block height and block age for each network you add, next to the fee and RPC latency, refreshed every 15 seconds. Each row is tagged Live, Lagging or Stalled. On most EVM chains a newest block older than 15 seconds counts as lagging and one older than 90 seconds as stalled; Solana gets 5 and 30 seconds, Ethereum 30 and 120. Solana pulse adds the current slot and epoch progress. Chain pulse shows the latest Base or Robinhood Chain block number, with an age that keeps counting between refreshes and turns amber after a minute without a new block.

• Chain pulse
• Chain status
• Solana pulse

• Block time
• RPC endpoint
• Finality
• Blockchain explorer