Block height is a block’s sequential position in a particular blockchain, counted from its genesis block. It identifies chain position; it does not state the exact time, number of transactions, or finality of a transaction.
How numbering works
The first block is height 0; each block that extends the chain receives the next height. In Bitcoin, blocks are added on average about every ten minutes, while Ethereum numbers proposed blocks on its slot schedule and some slots can be missed. During a fork or reorganization, competing blocks can share a height; the network’s consensus rules determine which history is accepted.
Height, time, and confirmations
A height is an ordinal coordinate, not a clock. Block timestamps and average production intervals provide separate time information, and neither makes every block arrive on schedule. A transaction’s confirmation depth depends on how many later blocks build on the block that included it. Height alone does not show that a particular payment is final.
Where height is useful
Explorers, node software, and protocol documentation use heights to identify a block and refer to historical state. Bitcoin subsidy halvings and some planned rule changes are tied to heights. On proof-of-work networks, chain selection considers accumulated work, not simply which branch has the largest raw block count; proof-of-stake systems use their own fork-choice and finality rules.
Common misconception
A block height cannot be converted into an exact calendar time by multiplying it by the target interval. Production varies, and a chain reorganization can change the canonical block at a recent height. Use a current node or reputable explorer when an exact block record matters.
Social Media Sentiment
- An April 2024 Bitcointalk thread asked whether Bitcoin’s halving began at height 839,999 or 840,000; replies distinguished the last block with the old subsidy from the first block with the new one. This narrow technical exchange is not a survey of wider opinion. the April 2024 discussion about the Bitcoin halving block
Last updated: 2026-10
Related Terms
See Also
- What Happens to Bitcoin When All 21 Million Are Mined?
- What Is MEV?
- Are Layer 2 Networks Actually Decentralized?
- ChangeNOW
Sources
- Bitcoin Developer Guide: Block Chain — Explains block ordering, previous-header hashes, full-node validation, and how the chain records transaction history.
- Ethereum.org: Blocks — Documents Ethereum block structure, block numbers, and the network’s slot-based production model.