Bitcoin difficulty set for another jump on October 29: which Antminers still pay
Bitcoin miners are heading into a second difficulty increase in a row. According to mempool.space, the next retarget at block 973,728 is expected around October 29, and as of the morning of October 27 the estimate stood at about +6.4%. Other trackers put it between +5.2% and +6.1%, and the figure will keep moving until the last block of the epoch.
What already happened
On October 16, at block 971,712, difficulty rose 5.92% from 132.72T to 140.58T, the highest level since early March, though still about 10% below the October 2025 record of 155.97T, as BlockOps Mining notes. The seven-day average hashrate climbed back above 1 ZH/s, reaching about 1,080 EH/s according to Cointribune, while hashprice slipped to $36.04 per PH/s per day from $40.42 on September 25.
The rebound is happening even as public miners leave. Crypto Insider reports that IREN plans to exit bitcoin mining by December 31, 2026, freeing 23.2 EH/s, and that public companies moved 75 EH/s to AI tenants in the first half of the year. The capacity is being replaced elsewhere: Bitcoin.com points to Bitdeer, whose self-mining capacity reached 82.3 EH/s in September.
Where the line runs for popular Antminers
The key number for any machine is the electricity price at which it stops covering its power bill. At a hashprice of roughly $36, published estimates look like this:
- Antminer S21 XP+ Hydro: about 12.8 cents per kWh (Crypto Insider).
- Antminer S21 XP (270 TH/s, 3,645 W): about 11.3 cents; at 7 cents it clears roughly $3.80 a day (BlockOps).
- Antminer S21 Pro: about 9.4 cents (Crypto Insider).
- Antminer S21 (200 TH/s, 3,500 W): about 8.75 cents; at 9 cents it already mines at a loss (BlockOps).
- Antminer S19 XP: about 6.6 cents (Crypto Insider).
What changes after October 29
Crypto Insider expects hashprice to drop to about $33.87 after the retarget if bitcoin holds near $80,382. Running BlockOps' own S21 XP math at that level, our estimate is about $9.14 a day in gross revenue, roughly $3.02 of margin at 7 cents, and a break-even rate near 10.5 cents. For the S21 the line moves to about 8.1 cents. Because the power bill stays the same, every percent of difficulty takes a larger share of margin than of revenue.
Practical takeaways
- If your all-in rate is above 9 cents, the S21 and S19 XP class are at or below break-even after the retarget.
- Check your hosting contract for curtailment terms before winter: storms can knock hashrate off the network, and your machines with it.
- The Fed decision on October 27 and 28 lands just before the retarget and will move the bitcoin price, which matters as much as difficulty for daily revenue.
All figures are estimates from the sources above and change with every block and every move in price.