Difficulty Adjustment

Definition

Difficulty adjustment is Bitcoin's mechanism for changing how hard it is to find a valid proof-of-work block as mining conditions change. On Bitcoin mainnet, the target is recalculated after each interval of 2016 blocks, using elapsed block time to move the average toward approximately ten minutes per block. More demanding difficulty corresponds to a lower numerical target that fewer hashes satisfy. If blocks have arrived too quickly, the next adjustment generally makes mining harder; if they have arrived too slowly, it generally makes mining easier, within the protocol's adjustment limits. The mechanism does not schedule individual blocks, which remain probabilistic, and it does not guarantee stable miner income. Increased hash rate can make blocks arrive faster before the next adjustment. Other networks, including Bitcoin testing networks, can use different rules, so mainnet's interval should not be treated as universal across cryptocurrencies.