Bitmain Antminer S21+ (235Th)

The Antminer S21+ delivers 235 TH/s of SHA-256 hashrate at 3,875W wall draw and 16.49 J/TH efficiency. Bitmain rates hashrate at plus or minus 3 percent and power at plus or minus 5 percent, meaning real world output typically lands between 228 and 242 TH/s depending on ambient temperature, voltage quality, and firmware version. Built on the BM1370 5nm chip, the same silicon powering the Antminer S21 Pro and Antminer S21 XP.

At MillionMiner's $2,739 price, the S21+ works out to approximately $11.65 per terahash acquired. That compares to roughly $15.00 per terahash on the Antminer S21 XP and $13.00 per terahash on the Antminer S21 Pro. The S21+ is the cheapest per terahash option in the current S21 lineup, which is why capital constrained fleet operators frequently choose it over more efficient alternatives.

The S21+ produces 235 TH/s at 16.49 J/TH for $2,739. The S21 XP produces 270 TH/s at 13.5 J/TH for $4,051. The XP delivers 15 percent more hashrate at 22 percent better efficiency but costs 48 percent more per unit. At electricity rates below $0.05 per kWh, the S21+'s lower acquisition cost wins on total Bitcoin mined per dollar invested. Above $0.07 per kWh, the XP's efficiency recovers its premium within 12 to 18 months. Know your rate before choosing.

Both produce nearly identical hashrate: S21+ at 235 TH/s and S21 Pro at 234 TH/s. The Pro runs at 15.0 J/TH versus the S21+ at 16.49 J/TH, which is 9 percent better efficiency per terahash. Acquisition cost is where they diverge: the S21+ sits at a lower price point, making it the value tier of the two. For operators prioritizing upfront capital efficiency, the S21+ wins. For operators prioritizing long term operating cost, the Pro wins. The math inverts around $0.06 per kWh depending on exact current pricing at MillionMiner.

Profitability depends heavily on your electricity rate. At current April 2026 network conditions: gross daily revenue runs approximately $7.66 to $8.06 per unit. At $0.06 per kWh, daily net profit is around $2.48 per unit. At $0.08 per kWh (MillionMiner's default calculator), daily net drops to roughly $0.22. At $0.10 per kWh, the unit runs at slight daily loss. At $0.04 per kWh industrial rates, daily net reaches approximately $7.97. The S21+ operates profitably on cheap power and breaks even at mid tier rates.

Any SHA-256 proof of work cryptocurrency. Bitcoin (BTC) is the primary target. Other SHA-256 coins include Bitcoin Cash (BCH), Bitcoin SV (BSV), Fractal Bitcoin (FB), Elastos (ELA), and DigiByte (DGB SHA-256 chain). Merged mining some of these alongside Bitcoin through supporting pools like ViaBTC and F2Pool adds marginal revenue without splitting your hashrate.

240V AC on a dedicated 20 amp circuit is the recommended deployment. At 220V the unit draws approximately 17.6 amps continuously, fitting within a 20 amp breaker with headroom. At 110V it draws roughly 35.2 amps, requiring a dedicated 40 amp residential circuit that most North American homes need electrical panel work to install. European, Middle Eastern, and Asian operators at 220 to 240V single phase run the S21+ directly off standard household power with appropriate breaker capacity. PSU and power cables ship included.

A $100,000 hardware budget at MillionMiner's $2,739 price buys 36 S21+ units producing 8,460 TH/s combined. The same budget buys 24 Antminer S21 XP units producing 6,480 TH/s. The S21+ fleet has 31 percent more total hashrate pointed at the Bitcoin network. On daily mining revenue, that translates to 31 percent more total Bitcoin mined. The tradeoff is cumulative electricity: the S21+ fleet burns approximately $1,650 more per month in extra power at $0.04 per kWh, or $3,300 more per month at $0.08 per kWh. Do the math on your specific rate before deciding.

The S21+ operating ceiling is 35 degrees Celsius, lower than the Antminer S21 XP at 45 degrees. In practice, this matters for operators in hot climate regions or facilities without climate control. Middle East, South Asian, and equatorial summer deployments regularly see ambient temperatures exceeding 35 degrees, which risks thermal throttling or shutdown on the S21+. Verify your facility stays within range during peak summer months or invest in cooling infrastructure before deploying S21+ fleets in hot climates.

75 dB from four high speed fans is standard industrial ASIC noise, comparable to a vacuum cleaner at close range. Suitable for garages, basements with adequate ventilation, dedicated mining rooms, workshops, outbuildings, and professional hosting facilities. Not suitable for bedrooms, living rooms, shared offices, or any shared living space. For home deployment, a closed door dedicated room is the minimum requirement to prevent noise complaints from household members or neighbors.

Setup takes under 15 minutes. Step one: connect the PSU to the miner and plug into a dedicated 240V outlet with at least 20 amp capacity. Step two: run an Ethernet cable from the miner to your router or managed switch. Step three: power on the unit and wait 60 seconds for boot. Step four: find the miner IP through your router's DHCP client list or using a tool like Advanced IP Scanner or Bitmain IP Reporter. Step five: open that IP in any web browser and log in with default credentials (root/root). Step six: navigate to Miner Configuration, enter your pool URL in stratum+tcp://pool.address:port format, set your Bitcoin wallet address or pool worker name, leave password blank or enter any placeholder, and save. Hashrate reaches the expected 228+ TH/s range within 10 to 15 minutes.

Any Stratum compatible pool works without special configuration. Foundry USA is the largest pool by network share with competitive FPPS payouts. AntPool is Bitmain's native pool with direct integration and low fees. F2Pool has a long operational track record and supports merged mining for BCH and BSV. ViaBTC offers multi algorithm support and accumulation mode payouts that reduce daily variance. Braiins Pool runs transparent Stratum V2 with built in fee rebates. Pool fees typically range from 0.5 to 2 percent.

Yes, with tradeoffs. Bitmain's stock firmware supports limited fan curve and frequency adjustments. Third party firmware including Braiins OS+ and Vnish unlocks aggressive autotuning that typically squeezes 3 to 7 percent additional hashrate at 5 to 10 percent more power draw. Underclocking for efficiency drops hashrate by 10 to 15 percent while improving J/TH by 8 to 12 percent, valuable during expensive peak rate periods. The BM1370 chips tolerate tuning well but aggressive overclocking increases thermal stress and shortens expected hardware lifespan.

Stock Bitmain firmware handles standard operation, pool configuration, and monitoring through the web interface. Third party firmware options include Braiins OS+ (autotuning and Stratum V2 support), LuxOS (LuxOR Tech's management platform optimized for industrial scale operations), and Vnish (popular for aggressive overclocking in Eastern European markets). First time operators should run factory firmware. Experienced fleet managers running 10+ units often deploy Braiins OS+ or LuxOS for unified management and efficiency tuning across the fleet.

Three issues surface most often. First, temperature warnings when ambient approaches the 35 degree ceiling, which occurs more frequently than on the Antminer S21 XP due to the tighter operating range. Solutions include improving facility ventilation, adjusting fan curves, or reducing ambient temperature. Second, occasional hashboard chip failures that reduce output until the affected board is replaced (standard Bitmain warranty repair). Third, fan bearing wear over 18 to 24 months of continuous operation, which triggers protective shutdowns and requires fan replacement. Budget approximately 3 to 5 percent of acquisition cost annually for replacement parts and maintenance.

For existing Bitmain fleets, integration requires zero configuration beyond network connection. The S21+ uses the same Bitmain firmware, web interface, pool configuration format, and management APIs as every other Antminer. Fleet tools including Foreman, Awesome Miner, Hive OS, and Braiins OS+ discover the unit automatically. Point it at your existing pool with your standard worker naming scheme. For mixed fleets running MicroBT Whatsminer or Canaan Avalon alongside Bitmain, unified dashboards handle all three brands. Network requirements: one Ethernet port per miner through a DHCP capable router or managed switch. Power requirements: one 20 amp 240V circuit per miner.

The Antminer S23 family (S23, S23 Hydro, Antminer S23E Hyd 2U) runs at 9.5 to 11.0 J/TH, significantly more efficient than the S21+. But S23 air cooled variants command much higher acquisition premiums and often ship with long lead times. The S21+ at $2,739 offers immediate availability and positive economics on cheap power right now. For operators building fleets immediately at sub $0.05 per kWh rates, the S21+ delivers the best cost per terahash available today. For operators with premium capital and multi year deployment horizons, the S23 generation may pay off on lifetime operating cost.

MillionMiner ships the Antminer S21+ factory sealed with Bitmain's standard factory warranty (typically 180 to 365 days from shipping depending on batch). Warranty covers manufacturing defects and hardware failures under normal operation. It does not cover damage from improper electrical installation, aggressive overclocking beyond factory specifications, or deployment outside the 5 to 35 degree operating range. MillionMiner routes warranty claims through direct Bitmain channels for faster resolution. PSU and power cables ship included. Free DDP delivery worldwide covers all customs clearance, import duties, and taxes.

Possible but with clear constraints. You need a dedicated 240V/20A circuit (most homes require electrical panel work to install one), a room or garage that can dissipate 3,875W of continuous heat (equivalent to three space heaters), ambient temperatures staying below 35 degrees Celsius year round, and tolerance for 75 dB industrial noise. For home miners with proper infrastructure, the S21+ can work. For most home deployments, the quieter Antminer S21 XP at 40 dB (per MillionMiner's spec) or hosted mining is the practical alternative. Winter deployment in cold climates turns the 3,875W heat output into free space heating.

For efficiency focused buyers, step up to the Antminer S21 XP at 13.5 J/TH. For operators with hydro cooling infrastructure, the Antminer S21 XP Hydro at 473 TH/s and 12.0 J/TH or the Antminer S23E Hyd 2U at 865 TH/s and 10 J/TH fit density optimized deployments. The Bitmain Antrack V1 Hydro-Cooling Rack provides infrastructure for any four hydro units. For operators wanting zero self hosting, MillionMiner's ASIC hosting service deploys S21+ fleets at managed facilities with industrial rates. For Kaspa diversification alongside Bitcoin, the Antminer KS7 at 45 TH/s offers algorithm spread.