Full-size ASICs
Antminer S21
by Bitmain, BM1368
The Antminer S21 is Bitmain's air-cooled industrial Bitcoin miner, released in 2023. It hashes about 200 TH/s at 3,500 W, about 17.5 J/TH, through four fans at around 75 dB. It needs 220 to 277 V power and Ethernet. It is one of the most efficient air-cooled miners, but it belongs in a garage or farm.
Published October 5, 2026. Updated October 5, 2026
| Item | Part | From the specs |
|---|---|---|
| 1 | Cooling | Four 120 mm fans, front to back airflow. About 75 dB |
| 2 | Case | 400 x 195 x 290 mm, 15.4 kg |
| 3 | Hashing chip | Bitmain BM1368 |
Key figures
- Hashrate
- 200 TH/s
- Power
- 3500 W
- Efficiency
- 17.5 J/TH
- Price range
- $2,500 to $4,000
Availability: sold new.
01
Specifications
- Hashrate
- About 200 TH/s (other S21 versions range from about 188 to 200 TH/s)
- Power draw
- About 3,500 W
- Efficiency
- About 17.5 J/TH
- Chip
- Bitmain BM1368
- Cooling and noise
- Four 120 mm fans, front to back airflow. About 75 dB
- Connectivity
- Ethernet (RJ45, 10/100 Mbit/s) only
- Power supply
- Built-in PSU, 220 to 277 V AC
- Size and weight
- 400 x 195 x 290 mm, 15.4 kg
- Open source
- No
- Release year
- 2023
- Firmware
- Bitmain stock firmware
02
Good and less good
Good
- About 17.5 J/TH, among the best for air-cooled miners.
- About 200 TH/s from one machine: roughly 166 Bitaxe Gammas.
- Sold new by Bitmain with warranty, and widely supported.
Less good
- Loud (about 75 dB) and produces 3.5 kW of heat.
- About 30,700 kWh a year: electricity is the main cost.
- Needs 220 to 277 V and a dedicated circuit.
- Much higher purchase price than used S19s.
03
Set it up on DirectPool
The S21 is configured from the web page at its IP address. Plug it into your router with a cable and find the IP in your router's device list.
Type exactly this
- Pool 1 URL
- stratum+tcp://stratum.directpool.io:3333
- Pool 1 Worker
- your_bc1_address.worker_name
- Pool 1 Password
- x
Choose your mining region
Showing Europe, Lithuania (main server).
Changing the location only changes the address shown above. Copy it into your miner settings and restart or reconnect the miner. Miners already connected stay where they are. Every server mines the same pool, with the same payouts.
Browser ping, measured live from this page
Europe, Lithuania...
North America, Chicago...
Asia, Jakarta...
This measures your browser connection, not your miner or the full relay-to-pool path.
Replace your_bc1_address with a Bitcoin address you control (bc1 or 3). The part after the dot is a name for this machine, so you can tell your miners apart. Addresses starting with 1 are not accepted.
- 1.Connect the miner to your router with a network cable. Antminers have no WiFi.
- 2.Find its IP address in your router's device list (or with Bitmain's IP Reporter tool and the IP Report button on the control board).
- 3.Open that address in a browser on the same network and log in. The default username and password are both root.
- 4.Open the pool settings page (Miner Configuration on older firmware, Settings or Pool on newer).
- 5.Enter the values above in Pool 1. Pools 2 and 3 are backups.
- 6.Click Save & Apply (or Save). The miner restarts its mining process; hashrate shows on the status page after a few minutes.
Common mistakes
- Leaving out stratum+tcp:// or :3333. The Antminer URL field takes the full address.
- Keeping the default root password. Change it, since anyone on your network could otherwise redirect your hashrate.
- Typing the Bitcoin address by hand in the Worker field. Copy and paste it.
- Plugging it into a normal household circuit without checking the load. These machines draw well over a kilowatt non-stop.
- Using a 110 to 120 V outlet or an undersized circuit. The S21 needs 220 to 277 V and a circuit rated for about 3.5 kW continuous.
- Running it outside its 5 to 40 °C operating range, or with the hot exhaust blowing back into the intake.
After a few minutes, paste your address on the pool page to see the machine. Small miners can take a while to send their first share.
04
Your odds with this miner
- Network difficulty
- Loading
- DirectPool, 1 h avg
- Loading
- Next block value
- Loading
Chance of finding at least one block, with 200 TH/s
| Solo | With DirectPool | |
|---|---|---|
| Per day | ||
| Per month | ||
| Per year |
If DirectPool finds a block, this miner would get about
Loading
These are chances, not schedules. Hashing has no memory: a miner that has not found a block is not closer to one. Open the full calculator
05
Electricity cost
Running all year at about 3,500 W, the Antminer S21 uses about 30,681 kWh a year.
| Price per kWh | Per year | Per month |
|---|---|---|
| 0.10 | 3,068 | 256 |
| 0.20 | 6,136 | 511 |
| 0.30 | 9,204 | 767 |
Same currency as your electricity price (dollars, euros, pounds). Real draw depends on firmware settings and frequency.
06
Where to buy
- Bitmain (official store)Ships to: Worldwide (official store)
- D-Central Technologies (Antminer S21)Ships to: Canada, ships worldwide
- Braiins Store (Bitmain miners)Ships to: Worldwide
- Maxi MinersShips to: EU (Czech Republic)
Typical price $2,500 to $4,000, checked October 5, 2026. Prices move, check the store. Plain store links. We earn nothing from them.
07
Questions
- Can I run an Antminer S21 at home?
- Only with a 220 to 277 V circuit rated for about 3.5 kW and a space where 75 dB and lots of heat are acceptable, like a garage or outbuilding with ventilation.
- Which settings do I enter for DirectPool?
- In the web interface, Pool 1 URL stratum+tcp://stratum.directpool.io:3333, Worker your bc1 address plus .worker, Password x. Save & Apply.
- How much electricity does it use?
- About 30,700 kWh a year at 3,500 W, so about 6,100 a year at 0.20 per kWh.
- S21 or S21 Hydro?
- The standard S21 is air-cooled and plugs in like other Antminers. Hydro versions are more efficient and quieter but need a liquid-cooling setup.
- Does DirectPool handle a 200 TH/s miner?
- Yes. Large miners connect the same way as small ones. If you want a fixed share difficulty, put d= and a number in the password field instead of x, for example d=500000.
08
Sources
- Bitmain: Antminer S21 product page (hashrate, power, efficiency, voltage)https://shop.bitmain.com/product/detail?pid=00020240311180613891frupBW6406B2, checked 2026-10-05
- D-Central: Antminer S21 product page (fans)https://d-central.tech/product/bitmain-antminer-s21, checked 2026-10-05
- Bitmain support: Antminer S21 specification (size, weight)https://support.bitmain.com/hc/en-us/articles/23794895251609-S21-Specification, checked 2026-10-16
- Kryptex: Antminer S21 200T device page (noise)https://pool.kryptex.com/device/asic/bitmain/antminer-s21-200th, checked 2026-10-05