The 15 largest increases in bitcoin’s mining difficulty since the network began in 2009, ranked by percentage change. A big increase means many miners had joined and blocks were coming in fast. Fourteen of the fifteen came in 2010 and 2011.
Data as of · all 467 difficulty adjustments from block 2,016 to block 971,712 (Oct 16, 2026), from mempool.space, cross-checked against Blockchain.com
| Rank | Date | Block | Change | Difficulty before | Difficulty after | Avg block time before | Year |
|---|---|---|---|---|---|---|---|
| 1 | Jul 16, 2010 | 68,544 | ▲ +300.00% | 45.39 | 181.54 | 2.4 min | 2010 |
| 2 | Jul 13, 2010 | 66,528 | ▲ +93.12% | 23.50 | 45.39 | 5.2 min | 2010 |
| 3 | May 26, 2011 | 127,008 | ▲ +78.15% | 244.1K | 434.9K | 5.6 min | 2011 |
| 4 | Jun 24, 2011 | 133,056 | ▲ +57.27% | 877.0K | 1.38M | 6.4 min | 2011 |
| 5 | Oct 21, 2010 | 86,688 | ▲ +55.95% | 1.4K | 2.1K | 6.4 min | 2010 |
| 6 | May 18, 2011 | 124,992 | ▲ +55.07% | 157.4K | 244.1K | 6.5 min | 2011 |
| 7 | Jun 15, 2011 | 131,040 | ▲ +54.59% | 567.3K | 877.0K | 6.5 min | 2011 |
| 8 | Feb 27, 2011 | 110,880 | ▲ +52.47% | 36.5K | 55.6K | 6.6 min | 2011 |
| 9 | Dec 9, 2010 | 96,768 | ▲ +51.67% | 8.1K | 12.3K | 6.6 min | 2010 |
| 10 | Nov 18, 2010 | 92,736 | ▲ +51.37% | 4.5K | 6.9K | 6.6 min | 2010 |
| 11 | Feb 24, 2010 | 42,336 | ▲ +49.59% | 2.53 | 3.78 | 6.7 min | 2010 |
| 12 | Nov 9, 2010 | 90,720 | ▲ +46.73% | 3.1K | 4.5K | 6.8 min | 2010 |
| 13 | Apr 21, 2010 | 52,416 | ▲ +46.61% | 7.82 | 11.46 | 6.8 min | 2010 |
| 14 | Oct 26, 2013 | 266,112 | ▲ +46.02% | 267.73M | 390.93M | 6.8 min | 2013 |
| 15 | Aug 15, 2010 | 74,592 | ▲ +45.32% | 352.16 | 511.77 | 6.9 min | 2010 |
Change = new difficulty ÷ old difficulty, minus 1, at each adjustment (every 2,016 blocks). Avg block time before = the time between the previous adjustment and this one, divided by the number of blocks in between; the target is 10 minutes. Difficulty is shown in K (thousands), M (millions) or T (trillions). Each figure matches Blockchain.com’s daily difficulty series, which sometimes records a change a day or two later. Of the 467 adjustments so far, 357 were increases; of the 15 shown, 14 date from 2010 and 2011 and one from 2013. For comparison, the latest adjustment on Oct 16, 2026 was +5.92%.
Mining difficulty sets how hard it is to find a new block. Every 2,016 blocks, about two weeks, the network compares how long those blocks actually took with the two-week target and resets difficulty so blocks keep arriving about every 10 minutes; one adjustment can change it by at most a factor of four.1 When miners add machines, blocks come faster and the next adjustment raises difficulty. These are the 15 biggest increases, from the network’s own adjustment history. Nearly all of the largest increases are from 2010 and 2011, when difficulty itself was a tiny number: the first of them lifted it from 45.39 to 181.54.23 For how many bitcoin listed miners hold, see the largest public miners by bitcoin held.
Difficulty rose 300.00% at block 68,544, from 45.39 to 181.54. In the 2,016 blocks before it, blocks had taken 2.4 minutes on average against the 10-minute target, a sign that more mining power had joined the network during the period.24 It came in 2010, one of the 14 entries in this table from 2010 and 2011.
Difficulty rose 93.12% at block 66,528, from 23.50 to 45.39. In the 2,016 blocks before it, blocks had taken 5.2 minutes on average against the 10-minute target, a sign that more mining power had joined the network during the period.25 It came in 2010, one of the 14 entries in this table from 2010 and 2011.
Difficulty rose 78.15% at block 127,008, from 244.1K to 434.9K. In the 2,016 blocks before it, blocks had taken 5.6 minutes on average against the 10-minute target, a sign that more mining power had joined the network during the period.26 It came in 2011, one of the 14 entries in this table from 2010 and 2011.
Difficulty rose 57.27% at block 133,056, from 877.0K to 1.38M. In the 2,016 blocks before it, blocks had taken 6.4 minutes on average against the 10-minute target, a sign that more mining power had joined the network during the period.27 It came in 2011, one of the 14 entries in this table from 2010 and 2011.
Difficulty rose 55.95% at block 86,688, from 1.4K to 2.1K. In the 2,016 blocks before it, blocks had taken 6.4 minutes on average against the 10-minute target, a sign that more mining power had joined the network during the period.28 It came in 2010, one of the 14 entries in this table from 2010 and 2011.
Difficulty rose 55.07% at block 124,992, from 157.4K to 244.1K. In the 2,016 blocks before it, blocks had taken 6.5 minutes on average against the 10-minute target, a sign that more mining power had joined the network during the period.29 It came in 2011, one of the 14 entries in this table from 2010 and 2011.
Difficulty rose 54.59% at block 131,040, from 567.3K to 877.0K. In the 2,016 blocks before it, blocks had taken 6.5 minutes on average against the 10-minute target, a sign that more mining power had joined the network during the period.210 It came in 2011, one of the 14 entries in this table from 2010 and 2011.
Difficulty rose 52.47% at block 110,880, from 36.5K to 55.6K. In the 2,016 blocks before it, blocks had taken 6.6 minutes on average against the 10-minute target, a sign that more mining power had joined the network during the period.211 It came in 2011, one of the 14 entries in this table from 2010 and 2011.
nPowTargetTimespan = 14 * 24 * 60 * 60, two weeks, and nPowTargetSpacing = 10 * 60), and src/pow.cpp, which limits each adjustment to a factor of 4, retrieved 2026-10-17.For information only. Not financial advice. See the terms of use.