Block Height
The count of blocks since the genesis block (which is at height 0).
Block height is the number of blocks between any given block and the genesis block, which sits at height 0. Block 1 is one above genesis. Block 840,000 - where the most recent halving occurred - is 840,000 above it.
Height is the canonical way to refer to a point in Bitcoin's history. Timestamps are imprecise (miners control their own clocks within a window). Dates depend on calendar conventions. But block heights are integer, monotonic, and identical for every node on the network.
Most of Bitcoin's protocol-level events are scheduled by height, not by date:
- Halvings happen at heights 210,000, 420,000, 630,000, and so on (every 210,000).
- Difficulty retargets happen at heights that are multiples of 2,016.
- Soft forks (Taproot, SegWit, BIP-66, etc.) activate when a target height is reached or signaling thresholds clear in a retarget window.
If you want a single number that locates "what's happening on Bitcoin right now," it's the current block height. See the Node page for the live current height.
Key takeaways
- Counts blocks from the original genesis block
- Used for referencing specific points in the blockchain
- Essential for protocol events tied to block intervals