Bitmain Antminer S21 PRO (234Th)

234 TH/s SHA-256 at 3,510W and 15 J/TH. ±3 percent hashrate and ±5 percent power tolerance. The "PRO" designation means premium chip binning from Bitmain's 5nm production: same chip architecture as the S21 and S21+, but chips selected for higher efficiency. The PRO achieves 234 TH/s at 15 J/TH versus the S21+ at 235 TH/s and 16.5 J/TH, virtually identical hashrate at 10 percent better efficiency.

S21 PRO at 234 TH/s, 3,510W, 15 J/TH, $3,083. S21+ at 235 TH/s, 3,876W, 16.5 J/TH, $3,083. Same price and effectively same hashrate. The PRO draws 366W less power for the same output. At $0.08 per kWh: PRO saves $0.70 daily electricity, producing $1.87 daily profit versus the S21+ at approximately $1.17. The PRO is the better buy at the same price. Over one year, the PRO saves $256 per unit in electricity compared to the S21+.

S21 XP at 270 TH/s, 3,645W, 13.5 J/TH, $4,051. S21 PRO at 234 TH/s, 3,510W, 15 J/TH, $3,083. The XP costs $968 more but delivers 36 TH/s more hashrate at 10 percent better efficiency. The XP produces approximately $3.81 daily profit versus the PRO at $1.87. The XP's $968 premium pays for itself in approximately 500 days. For shorter deployment horizons, the PRO at lower CapEx may deliver better total return. For deployments exceeding 18 months, the XP's efficiency advantage compounds.

A3 Pro Air at 290 TH/s, 3,625W, 12.5 J/TH, $4,490. S21 PRO at 234 TH/s, 3,510W, 15 J/TH, $3,083. The A3 Pro Air delivers 24 percent more hashrate at 17 percent better efficiency for $1,407 more. The A3 Pro Air produces approximately $3.81 daily profit versus the PRO at $1.87. The A3 Pro Air's premium pays back in approximately 726 days. The PRO wins on CapEx at $13.17 per TH versus $15.48 per TH for the A3 Pro Air.

Most distributor sources confirm 220 to 277V. MM lists 100 to 240V but at 3,510W on 110V the unit would draw approximately 31.9 amps, which exceeds any standard residential circuit. Practical deployment requires 220V+ circuits. At 220V draws approximately 16 amps. At 277V draws approximately 12.7 amps. Verify actual voltage range with MillionMiner before planning 110V deployment.

Yes. MillionMiner calculator at $0.08 per kWh: +$1.87 daily ($8.69 revenue minus $6.82 electricity). Monthly: +$56.10. At $3,083 acquisition: payback approximately 55 days. At $0.07 per kWh: +$2.79 daily, payback approximately 37 days. Profitable at any electricity rate below approximately $0.10 per kWh at April 2026 conditions. Not the most profitable miner available, but profitable at a lower CapEx entry than the S21 XP or A3 Pro Air.

Yes. BraiinsOS+ supports S21 series hardware. BraiinsOS+ provides autotuning (automatically optimizes chip voltage and frequency for best efficiency at your target power), per chip performance data, and pool management. Operators using BraiinsOS+ on S21 hardware typically achieve 2 to 5 percent efficiency improvements over stock firmware, pushing the PRO from 15 J/TH toward 14.3 to 14.7 J/TH range. Vnish firmware is another third party option. The Antminer firmware ecosystem is the most developed in the industry.

75 to 76 dB from four cooling fans. Standard industrial ASIC noise. Same as the S21 XP, S23, and most current generation Bitcoin miners. Requires dedicated mining space: warehouse, container, garage with sound isolation, or professional hosting. Not suitable for shared residential or office environments.

ASIC Marketplace and CryptoMinerBros list 450 x 219 x 293 mm. MM lists 400 x 195 x 290 mm. Mining Now lists 18.5 kg. MM lists 20 kg. MM body copy mentions 13.8 kg (contradicts the 20 kg spec). Multiple dimensions and weights in circulation — verify with MillionMiner which specific chassis version ships.

ASIC Marketplace and CryptoMinerBros list -20 to 45 degrees Celsius. MM lists 5 to 45 degrees Celsius. One Miners lists 0 to 40 degrees Celsius. If -20 to 45 is accurate (matching the Bitdeer A3 Pro Air), the S21 PRO supports cold climate container deployment without intake heating. Verify with Bitmain documentation.

All SHA-256 proof of work cryptocurrencies. Bitcoin (BTC) primary. Bitcoin Cash (BCH), Bitcoin SV (BSV), eCash (XEC), and other SHA-256 chains. AuxPoW merged mining through compatible pools. QUAI (SHA-256 chain) is noted by Kryptex as potentially the most profitable SHA-256 coin at certain conditions.

Yes. The S21 PRO ships with a built in PSU. C19 power connector with 20A cable. Connect directly to 220 to 277V outlet. No external PSU to source.

Standard Antminer setup. Connect power cable to 220V+ outlet. Connect Ethernet cable to router or switch. Find miner IP through Bitmain IP reporter, router DHCP, or network scanning. Open Antminer web interface, configure SHA-256 pool URL and BTC wallet address. Verify hashrate stabilizes at approximately 234 TH/s within 10 to 15 minutes.

Every major SHA-256 pool: Foundry USA, AntPool, F2Pool, ViaBTC, Braiins Pool, Luxor, OCEAN, and all SHA-256 compatible pools. Standard Stratum protocol. No restrictions.

365 day Bitmain manufacturer warranty per ASIC Marketplace and CryptoMinerBros. This is among the longest warranties in the ASIC industry. Covers manufacturing defects and hardware failures under normal operating conditions. BT-Miners lists 6 months which may reflect distributor specific terms rather than manufacturer warranty. Verify warranty duration through MillionMiner as the selling distributor.

Standard air cooled Antminer maintenance. Quarterly dust cleaning of four fan intake and exhaust. Annual fan bearing inspection. Monitor hashrate through Antminer web interface or BraiinsOS+ dashboard. Bitmain's S21 platform is well established with years of field reliability data across the S21 family.

Yes. MillionMiner hosting facilities accept S21 series hardware. At $0.07 per kWh hosted, daily electricity drops to $5.90, profit rises to +$2.79 daily. At $0.05 per kWh (some facility rates): +$4.48 daily, payback under 25 days. Hosting eliminates facility, noise, and infrastructure management for the operator.

For first time miners with access to 220V+ circuits and dedicated mining space, the S21 PRO is an excellent entry at $3,083. Lowest CapEx among currently profitable 200+ TH/s miners in stock. Bitmain's Antminer firmware is the most documented in the industry with extensive community guides. The 365 day warranty provides new buyer protection. For first timers without dedicated space or 220V circuits, professional hosting through MillionMiner eliminates infrastructure complexity.

The S21 PRO is the best value in MillionMiner's in stock Bitcoin mining lineup for buyers who prioritize low CapEx over maximum efficiency. At $3,083 with +$1.87 daily profit and approximately 55 day payback at $0.08 per kWh, the economics are solid. Buy the PRO if: you want the most affordable currently profitable Bitcoin miner with sub-16 J/TH efficiency, you value Bitmain's firmware ecosystem and BraiinsOS+ compatibility, or you are building a fleet where per unit CapEx matters more than per unit efficiency. Consider the S21 XP ($4,051) if you want 10 percent better efficiency and 15 percent more hashrate at higher CapEx. Consider the Bitdeer A3 Pro Air ($4,490) if you want 12.5 J/TH efficiency with cold climate deployment capability.

Within S21 family upgrades: S21 XP (270 TH/s, 13.5 J/TH, $4,051), S21 XP Hydro (473 TH/s, liquid cooled, $6,899), S21+ Hyd (319 TH/s, liquid cooled, $3,137). Next generation: Bitmain S23 (318 TH/s, 11 J/TH, $8,103). Competing manufacturers: Bitdeer A3 Pro Air (290 TH/s, 12.5 J/TH, $4,490). For fleet diversification: Bitmain KS7 (45 TH/s Kaspa, $2,123), Bitmain L9 (17 GH/s Scrypt, $3,990).