Definition
Block height is the sequential number assigned to each block in a blockchain, starting from zero at the genesis block and increasing by one with every new block added.
Why It Matters for Solo Mining
When you’re solo mining, block height helps you track exactly where the network is and whether your mining software is synced properly. If your full node shows a different block height than what blockchain explorers report, something’s wrong with your connection. Block height also matters because some cryptocurrencies change their mining rewards or difficulty adjustments at specific heights—like Bitcoin’s halving events that happen every 210,000 blocks.
How It Works
Think of block height as page numbers in a book that everyone’s writing together. The genesis block is page 0, the next block is page 1, and so on. Every time a miner successfully mines a block, they’re adding the next page number to the blockchain.
The block height is stored in the block header data and gets referenced by every subsequent block. When your mining software receives a new block through the P2P network, it checks the height to make sure the blocks are in the correct order. If someone tries to insert a block with the wrong height, the network rejects it.
Block height is especially important during forks. When two miners find blocks at nearly the same time, you temporarily have two competing chains at the same height. The network resolves this by eventually accepting whichever chain grows longer, and the losing block becomes an orphan block.
Example
As of late 2026, Bitcoin’s block height is around 870,000+. This means roughly 870,000 blocks have been mined since Satoshi created block 0 back in January 2009. If you’re solo mining Bitcoin and your node shows block height 870,250 while a block explorer shows 870,300, your node is 50 blocks behind—about 8 hours of catching up needed.
Another practical example: Bitcoin’s next halving will happen at block height 1,050,000 (around 2026), when the mining reward drops from 3.125 BTC to 1.5625 BTC per block.