BTC Difficulty: 125.81T
How hard the mining puzzle is right now. Bitcoin re-sets this about every two weeks so a new block keeps arriving roughly every 10 minutes, no matter how many machines join or leave.
A number showing how hard it currently is to find a valid block, measured against the very first block in 2009, which had difficulty 1.
It rises when more mining machines join and falls when they leave, always chasing the same 10-minute block target. For example, if difficulty rises 5% at one adjustment, about 5% more computing power joined during the previous two weeks, and every existing miner now earns roughly 5% less per machine.
A rare drop of several percent means a lot of machines were switched off.
Taken as blockchain.info publishes it. Bitcoin recalculates it every 2,016 blocks — about two weeks — by comparing how long those blocks actually took against the two weeks they were meant to take.
It **only** changes in steps roughly every two weeks, so a flat line between steps is normal, not a data gap. It reacts to what miners already did and **cannot** tell you what they will do next.
blockchain.info charts API · full history 2009+