Monitor & control your Antminer S21 from anywhere
AntminerTools gives you live hashrate, per-chain chip & PCB temperatures, power draw and remote reboot for your Antminer S21 fleet — on your phone or desktop, with no port forwarding and no VPN. Setup takes 2 minutes.
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Antminer S21 — models & specifications
Manufacturer-rated values; they vary by batch and work mode. AntminerTools reads live values directly from each unit.
| Model | Hashrate | Power | Cooling |
|---|---|---|---|
| Antminer S21 XP Hyd. | 473 TH/s | 5676 W | Hydro |
| Antminer S21 XP | 270 TH/s | 3645 W | Air |
| Antminer S21+ Hyd. | 319–395 TH/s | 4785 W | Hydro |
| Antminer S21 Hyd. | 302–335 TH/s | 5360 W | Hydro |
| Antminer S21 / S21+ / S21 Pro | 151–235 TH/s | ~3500 W | Air |
| Antminer S21 Immersion | 215–301 TH/s | 4800 W | Immersion |
How to monitor your Antminer S21
Run the lightweight connector agent on any PC or Raspberry Pi on your farm's network, click Scan, and every Antminer S21 on your subnet appears automatically — model, worker name, serial and MAC included. From then on it's live stats every 30 seconds.
Everything you get for your Antminer S21
Running the Antminer S21 day to day — what to watch
Antminer S21 rigs mine SHA-256 (Bitcoin). Specs tell you what the machine can do; day-to-day monitoring is about noticing early when it stops doing it. Here is what experienced operators watch on this model, and how to automate it.
Temperatures and cooling
Air-cooled S21 and S21 Pro units are happiest with chip temperatures in the 55–75 °C band in a ~25 °C room; sustained readings above 85 °C are where damage risk starts, which is why the default high-temp alert fires there. One quirk worth knowing: hydro variants (S21 Hyd., S21+ Hyd., S21 XP Hyd.) report zeros in the usual chip-temp field and expose the real values in a separate sensor array — AntminerTools reads the correct sensor automatically, so hydro dashboards show true temperatures instead of a fake 0 °C.
Power, efficiency and what they cost
Across the variants above, efficiency works out to roughly 12–23 J/TH at wall power — the Antminer S21 XP Hyd. is the efficiency leader of the family. At $0.06/kWh, every 100 W of extra draw costs about $4.30 a month, which is why the dashboard tracks efficiency per unit and not just raw hashrate.
The signals that matter
On the S21 family the number that drifts first is usually the 30-minute average hashrate: a single hashboard dropping out shows up as roughly a one-third dip long before the 5-second rate makes it obvious. Watch efficiency (J/TH) too — a unit that suddenly needs more watts per terahash at the same wall power usually has a cooling problem, not a pool problem.
If a fresh S21 shows zero hashrate for the first few minutes after a reboot, that is normal warm-up; AntminerTools waits ten minutes before judging a restarted miner so you do not get false alarms during ramp-up.
Recommended alert setup for the Antminer S21: a high-temperature rule at 85 °C chip temp, a hashrate-zero rule with auto-restart (a ten-minute boot grace stops false alarms after reboots), and an offline rule that emails you about a minute after a unit stops answering. All three take under a minute to create in Alerts — see the docs for details, or the guide to monitoring your fleet remotely.
Antminer S21 monitoring — frequently asked questions
How do I monitor my Antminer S21 remotely?
Create a free farm, run the connector agent on any PC or Raspberry Pi on the same network as your Antminer S21, then hit Scan. You'll see live hashrate and temperatures within a minute, from anywhere — no port forwarding, no VPN, no static IP.
Can I see Antminer S21 temperatures and get overheat alerts?
Yes. AntminerTools reads per-chain chip and PCB temperatures every 30 seconds and can automatically put an Antminer S21 to sleep if it overheats, plus email you on the Unlimited plan.
Does it work with every Antminer S21 variant?
Yes — every Antminer S21 running stock Bitmain firmware with the standard web interface is supported, including Hydro and immersion variants, with special handling for water-cooled temperature sensors.
How much does Antminer S21 monitoring cost?
Free for 1 farm and up to 4 miners with full monitoring and remote control. Paid plans add capacity from $3/mo, and email alerts + remote desktop on Unlimited.
Start monitoring your Antminer S21 — free
Create your account, run the agent, and see every Antminer S21 live — before your coffee gets cold.
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