OneMiners★ Featured✓ Verified sellerExtended warrantyPay in instalmentsIn stock, fast deliveryAntminer T21 - 233 TH/sHost with them from $0.0364/kWh, $118 a monthShips from United States · checked 23 h ago
The calculator from our free widget: every payback on this page follows it.
Income a day
$8.52
Power a day
−$3.87
Hosting a day
—
Profit a day
$4.65
Payback at $996
—
Profit and payback are estimates from today's coin prices and network difficulty, before pool fees, hosting and taxes. They change every day. Not financial advice.
Rankings use the algorithm's main coin (BTC for SHA-256, LTC + DOGE for Scrypt): small side chains may pay more per hash today but can't absorb much hashrate.
The Bitmain Antminer T21 (233Th) is an ASIC miner by Bitmain for the SHA-256 algorithm, rated at 233 TH/s on 4,427 W. It came out in February 2024. Its efficiency of 19.0 J/TH is close to the median SHA-256 miner we track (20.4 J/TH). At $0.036/kWh it ranks #108 of 299 SHA-256 miners by daily profit, earning about $4.65 a day mining BTC. The best price on AsicProfit is $996. At today's rates it would pay for itself in about 215 days. At 75 dB it belongs in a dedicated mining site or hosting facility.
Questions and answers 6
Ask about this miner. Verified accounts ask and answer, sellers answer as their store, and every post is checked before it shows.
Yusuf D. · Oct 26, 2026 · about another version
T21 shows warning J1:2 and power voltage read failed. What does it mean?
AsicProfit SupportAsicProfit · Oct 27, 2026
It points to the power side: the control board could not read the supply voltage, and the miner restarts. Measure each phase under load, not just at idle, and check the PDU sockets and cable terminations, since loose pins at the back of the socket are a known cause. If all three phases are healthy, the power supply is the next suspect. A unit under warranty should go back to Bitmain or an authorised repair centre.
Felix W. · Oct 22, 2026 · about another version
Is the T21 three-phase? I only have single-phase 240V at home.
AsicProfit SupportAsicProfit · Oct 24, 2026
Yes, the standard T21 ships for 380-415V three-phase input, which surprises many buyers because most Antminers in this class are single-phase. Owners confirm it needed electrical upgrades and three-phase PDUs. A few hobbyists run modified T21s on single-phase power supplies at reduced wattage, but that is a do-it-yourself conversion outside the warranty. Check your supply before you order.
Lucas O. · Oct 17, 2026 · about another version
can i just pull the plug on a T21 to switch it off
AsicProfit SupportAsicProfit · Oct 18, 2026
Not on the T21. An owner reported that its three-phase connector is not designed to be pulled under load, and if neutral breaks before the live pins it can damage the cable and power supply. Switch it off at the breaker first, then unplug. Frequent hard power cycling is also hard on solder joints, so fix the cause of any overheating rather than repeatedly cutting power.
Mark J. · Oct 15, 2026 · about another version
Why is the T21 cheaper than the S21, and is it the better buy?
AsicProfit SupportAsicProfit · Oct 15, 2026
The T21 does 190 TH/s at 19 J/TH, while the air-cooled S21 does 200 TH/s at 17.5 J/TH. You pay less up front but more electricity per terahash, so the T21's margin shrinks faster when difficulty rises or the Bitcoin price falls. It also needs three-phase power. With cheap three-phase electricity it can make sense; otherwise compare both in the calculator on this page at your power price.
Dmitri V. · Sep 29, 2026 · about another version
My T21 keeps overheating in summer and some boards now show 0 of 108 chips. Hardware or cooling?
AsicProfit SupportAsicProfit · Oct 1, 2026
It can be both. Owners report T21s struggling in hot containers, with corner chips running much hotter than the rest, and boards that lose chips after a restart. Check fans and intake temperature, reseat the hashboard and control board cables, and test boards one at a time. Repasting the heatsinks has helped several owners. Faulty PDU socket pins that drop a phase can also cause odd chip errors. Underclocking through the hottest months is a common workaround.
David C. · Sep 28, 2026 · about another version
How loud is the T21 and how much heat does it put out?
AsicProfit SupportAsicProfit · Sep 28, 2026
It is listed at about 75 dB, which is not suitable for a living space. Nearly all of its roughly 3,610 W becomes heat, about 12,300 BTU per hour, so the room needs strong ventilation or ducting for the exhaust. The listed operating range is 5 to 45°C, but owners advise keeping intake air well below the top of that range for long life.
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