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

One datapoint per retarget block (every 2016 blocks, ~2 weeks). Each row pulls the difficulty + realised hashrate over that epoch directly from our own Bitcoin Core 31 node via getblockheader and getnetworkhashps. Difficulty is flat between retargets by protocol, so the chart draws a step function aligned to each adjustment.

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 973,728.