Difficulty adjustment

Difficulty adjustment is a protocol rule that changes how hard it is for miners to add new blocks to a proof-of-work blockchain. The adjustment keeps block production close to the network’s target schedule even as mining power rises or falls. On Bitcoin, mining difficulty adjusts every 2,016 blocks. If blocks were mined too quickly during the previous period, difficulty increases. If blocks were mined too slowly, difficulty decreases. This keeps Bitcoin’s block time near the intended average of around 10 minutes.

If many new miners join Bitcoin and blocks start being found faster than expected, the next difficulty adjustment raises the mining difficulty so blocks return closer to the 10-minute target.