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# height

The block’s height above genesis — `0` is the genesis block, matching
Bitcoin Core’s [`CChain`](https://github.com/bitcoin/bitcoin/blob/master/src/chain.h)
indexing convention.

```
let height: Int
```

## Discussion> Warning: Height is **not** a reorg-safe identifier. Two different
> blocks can share the same height while a reorg is in flight. Use
> ``doc://BitcoinKernel/documentation/BitcoinKernel/BlockTip/hash`` for chain identity and reserve ``doc://BitcoinKernel/documentation/BitcoinKernel/BlockTip/height`` for UI display
> (progress bars, status labels) and for computing
> ``doc://BitcoinKernel/documentation/BitcoinKernel/BlockchainSync/Update/verificationProgress``.