Bitcoin’s Biweekly Difficulty Reset Keeps Blocks on Schedule

The Bitcoin protocol resets mining difficulty every 2,016 blocks, roughly every two weeks, to keep the average time between blocks near 10 minutes. The network recorded an 11.16% difficulty cut on Feb. 7, 2026 and a 14.7% increase on Feb. 19, 2026 after a severe weather event affected miners in the United States.

For each retarget period nodes compare the actual time it took to mine the previous 2,016 blocks against the 20,160-minute target implied by a 10-minute block design. If blocks were found faster than the target, difficulty rises for the next period; if they were slower, difficulty falls. Each node calculates the new level from block timestamps without a vote. Consensus rules limit any single retarget to a maximum fourfold increase or a 75% decrease.

Winter Storm Fern brought extreme cold to Texas and other U.S. mining regions in late January 2026. Several large operators powered down rigs to avoid stressing the electrical grid. Network hashrate fell an estimated 30%–40% from a prior peak near 1.13 ZH/s (about 1,130 EH/s) to roughly 663 EH/s. Two weeks of slower block production resulted in the 11.16% difficulty reduction on Feb. 7.

As rigs resumed operation, hashrate rose toward roughly 1 ZH/s and blocks were mined ahead of schedule in the following retarget period. The protocol responded with a 14.7% difficulty increase on Feb. 19, 2026, taking difficulty to a record 144.4 trillion while bitcoin’s market price was declining.

On June 13, 2026 difficulty fell about 9.91% during a retarget period that lasted about 15.6 days rather than the usual 14, indicating a gradual drop in hashrate. A roughly 15% slide in bitcoin’s price reduced margins for older mining hardware, and several publicly listed mining firms shifted some rigs and data-center capacity toward artificial intelligence and high-performance computing workloads. Seasonal demand patterns in Texas, including the ‘‘four coincident peak’’ period when large users curtail consumption, also reduced available power for mining.

An analyst described the February sequence as “the adjustment behaved exactly as designed,” characterizing the down-up swing as a response to a temporary supply shock rather than a change in the protocol’s rules.

As of late July the network was about 80% of the way through the current 2,016-block epoch, with early indicators pointing to a modest downward adjustment of about 1.2% at the next retarget near block 959,616. The protocol will run the same calculation at each epoch to determine difficulty based on observed block times.