Bitcoin difficulty

Every 2016 blocks (~2 weeks), Bitcoin adjusts mining difficulty to keep average block time at 10 minutes. If miners are finding blocks faster than target the difficulty goes up; slower, it goes down. The adjustment is capped at ±300%. This page shows the live state, the live countdown to the next retarget, and historical difficulty over time.

Difficulty over time

Snapshotted every 10 minutes from getblockchaininfo on our own Bitcoin Core 28 node. Default window: last 24 hours; difficulty is flat between retargets and steps at every 2016-block boundary, so the interesting view is week-scale or longer.

How the adjustment is computed

• Every 2016 blocks (one epoch), nodes recompute difficulty so that average block time over the just-completed epoch was 10 minutes.
• If the epoch took less than 2 weeks of wall-clock, difficulty increases proportionally (max +300%).
• If the epoch took more than 2 weeks, difficulty decreases proportionally (max -75%, capping a single retarget at a 4x drop).
• The "estimated change %" above projects forward from the observed average block time so far in the current epoch: (600 / avg_block_time - 1) × 100. It's a live estimate that moves as more blocks confirm; the actual retarget pins to whatever the wall-clock interval is at block 949,536.