The calculator from our free widget: every payback on this page follows it.
Income a day
$11.66
Power a day
−$4.46
Hosting a day
—
Profit a day
$7.20
Payback at $2,044
—
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 S21 Hyd (319Th) is an ASIC miner by Bitmain for the SHA-256 algorithm, rated at 319 TH/s on 5,104 W. It came out in February 2024. At 16.0 J/TH it is 21% more efficient than the median SHA-256 miner we track (20.4 J/TH). At $0.036/kWh it ranks #65 of 299 SHA-256 miners by daily profit, earning about $7.20 a day mining BTC. The best price on AsicProfit is $2,044. At today's rates it would pay for itself in about 284 days. It is water-cooled (hydro), so it needs a cooling loop and a dry cooler instead of fans.
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.
Chen L. · Oct 23, 2026 · about another version
How hot can my garage get before the S21 starts throttling?
AsicProfit SupportAsicProfit · Oct 24, 2026
Bitmain rates the air S21 for 0 to 45°C intake air, higher than the S19 series. In tests, stock firmware ran at full spec at 10 and 20°C and began underclocking near 40°C. Above 900 m altitude the limit drops 1°C per 300 m.
Janis O. · Oct 22, 2026 · about another version
My S21 stops hashing after a few minutes and shows a board error, any ideas?
AsicProfit SupportAsicProfit · Oct 23, 2026
Read the kernel log first. Common causes are a hashboard knocked loose in shipping, a bad data cable or an unstable power supply. One owner fixed this by replacing a faulty supply cable. Reseat cables and test boards one at a time. If it is under Bitmain's 365 day warranty, open a repair ticket rather than opening the case.
Dmitri V. · Oct 20, 2026 · about another version
S21 immersion, what oil temperature and flow does it need?
AsicProfit SupportAsicProfit · Oct 22, 2026
Bitmain lists the S21 Imm at 239 TH/s and 3,824 W in normal mode or 301 TH/s and 5,569 W in high mode, with inlet oil at 30 to 55°C and about 1 cubic metre per hour of coolant flow. It runs on three phase 380 to 415 V. High mode is less efficient.
Felix W. · Oct 3, 2026 · about another version
What does the S21 Hyd need for cooling and power?
AsicProfit SupportAsicProfit · Oct 5, 2026
The S21 Hyd makes about 335 TH/s at 5,360 W on three phase 380 to 415 V. It needs 8 to 10 L/min of deionized or pure water per unit, pressure up to 3.5 bar, pH 8.5 to 9.5, DN10 connectors, and inlet water up to 35°C in normal mode. Replace coolant once conductivity reaches 100 microsiemens per cm.
Oleh B. · Sep 28, 2026 · about another version
what plug does the S21 come with, C19 or C20?
AsicProfit SupportAsicProfit · Sep 29, 2026
Bitmain lists a P33 to P13 or C20 to P13 cord included with the air cooled S21. The P13 end goes into the miner's power supply; the C20 end plugs into a C19 socket on a PDU. Hyd and immersion versions use different power supplies, and the Hyd cord is not included.
Minjun P. · Sep 16, 2026 · about another version
Will an S21 run on a 16A circuit?
AsicProfit SupportAsicProfit · Sep 17, 2026
It is too tight. Bitmain lists about 3,500 W at the wall for the 200 TH/s air S21, on 220 to 277 V with up to 20 A on one input wire. At 230 V that is over 15 A continuously, which leaves no margin on a 16 A breaker. Give it a dedicated 20 A or larger circuit sized by an electrician.
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