Definition. The current estimated number of hashes required to mine a block. Mean Hash Rate is the related hash rate metric.

Technical. BTC difficulty is often denoted as the relative difficulty with respect to the genesis block, which required approximately 2^32 hashes. For better comparison across blockchains, values here are denoted in raw hashes. For ETH, values are only meaningful for the proof-of-work era, and difficulty is carried forward for intervals without blocks.