The Bitmain Antminer S21 Pro pushes the boundaries of SHA-256 mining efficiency with 234 TH/s at just 15 J/TH. As the mid-tier powerhouse in the S21 family, the Pro variant delivers a meaningful step up from the standard S21 in both hashrate and efficiency — making it one of the most compelling choices for serious mining operations in 2025 and beyond.
Built on the advanced BM1370 ASIC chip platform, the S21 Pro represents Bitmain’s continued refinement of their 5nm-class mining silicon. For operators seeking the best balance of performance, efficiency, and cost, the S21 Pro hits a sweet spot that few competitors can match.
Antminer S21 Pro Full Specifications
| Specification | Details |
|---|---|
| Manufacturer | Bitmain |
| Model | Antminer S21 Pro |
| Algorithm | SHA-256 |
| Hashrate | 234 TH/s |
| Power Consumption | 3,510W (±5%) |
| Efficiency | 15 J/TH |
| Noise Level | 75 dB |
| Weight | 15.0 kg |
| Dimensions | 400 x 195 x 290 mm |
| Operating Temperature | 5-45 °C |
| Cooling | 4 x high-speed fans (air-cooled) |
| ASIC Chip | BM1370 |
| Chip Count | ~360 |
| Input Voltage | 220-277V AC |
| Network Connection | Ethernet (RJ45) |
| Release Date | 2025 |
Performance Analysis
The S21 Pro’s 15 J/TH efficiency makes it one of the most power-efficient production miners available today. Compared to the standard Antminer S21 at 17.5 J/TH, the Pro delivers a 14% efficiency improvement while also adding 34 TH/s of additional hashrate — more hash, less waste.
Against the S21 XP (13.5 J/TH, 270 TH/s), the Pro offers a more accessible price point while sacrificing only modest efficiency. For operations that cannot justify the XP’s premium pricing, the Pro is the logical choice.
Looking at the competitive landscape, the Whatsminer M60S at 18.5 J/TH and 186 TH/s falls well behind the S21 Pro on both efficiency and raw hashrate. The S21 Pro firmly cements Bitmain’s lead in the current generation of air-cooled miners.
For a full ranking of miners by efficiency, see our Most Efficient Bitcoin Miners 2026 guide.
Profitability Snapshot
Estimated daily revenue and cost at current network difficulty (approximate, based on typical 2026 conditions). Actual results depend on Bitcoin price, network difficulty, and pool fees.
| Electricity Rate | Daily Power Cost | Monthly Power Cost | Viability |
|---|---|---|---|
| $0.05/kWh | $4.21 | $127 | Highly profitable — premium efficiency shines at cheap power rates |
| $0.08/kWh | $6.74 | $202 | Profitable — excellent margins at standard North American rates |
| $0.10/kWh | $8.42 | $253 | Profitable — the 15 J/TH efficiency keeps this viable where lesser miners struggle |
| $0.12/kWh | $10.11 | $303 | Marginal but viable — still operational at rates that kill S19-class machines |
Use our Bitcoin Mining Profitability Calculator for real-time estimates with your exact electricity rate, or check our Bitcoin Mining Electricity Cost by State & Province guide to find your local rate.
Best Use Cases
Mining Farms: The S21 Pro is a farm operator’s dream. At 234 TH/s in a standard Antminer form factor, it offers the highest hashrate density short of the S21 XP. Its 15 J/TH efficiency means your electricity bill scales more favorably than any S19-generation machine.
Serious Home Mining: Like all full-size Antminers, the S21 Pro requires 220V+ power and generates significant noise (75 dB). With proper ventilation, ducting, and a dedicated space, it works in residential settings — particularly in colder climates. Pair it with a D-Central cooling shroud to channel exhaust heat into your home.
Dual-Purpose Heating: The S21 Pro outputs approximately 11,976 BTU/h of waste heat. During Canadian winters, this is essentially a free space heater that also mines Bitcoin. See our Bitcoin Space Heater vs Electric Heater analysis for the full cost breakdown.
Fleet Upgrades: If you are running S19-era machines, the S21 Pro delivers nearly the same power draw (3,510W vs 3,068W for an S19j Pro) but more than doubles your hashrate. The ROI on the upgrade is compelling at any electricity rate under $0.10/kWh.
Compatible Firmware
| Firmware | Compatibility | Key Features |
|---|---|---|
| Stock (Bitmain) | Full support | Default firmware, basic configuration |
| Braiins OS+ | Supported | Autotuning, Stratum V2, power capping, remote management |
| Vnish | Supported | Advanced overclocking, custom profiles, immersion mode |
| LuxOS | Supported | Curtailment features, fleet management, API access |
For detailed installation instructions, see our guides:
- Antminer Firmware Compatibility Matrix 2026
- Braiins OS+ Setup & Configuration Guide
- Vnish Firmware Guide
- LuxOS Firmware Guide
- Antminer Firmware Update Guide
Common Issues & Repair
Common issues with the Antminer S21 Pro include:
- Hashboard failures: The BM1370 chips are densely packed. Thermal cycling and power surges can cause individual chip failures, reducing hashboard output. D-Central stocks BM1370 replacement chips.
- Fan errors: Fan speed sensor failures or bearing wear can trigger shutdown. Compatible replacement fans are available.
- Temperature warnings: The S21 Pro runs warm under full load. Ensure adequate airflow and ambient temperatures within the 5-45 degrees C range.
- Power supply issues: Ensure your PSU delivers clean, stable 220V+ power. Voltage sags cause erratic hashrate.
D-Central offers professional Antminer S21 Pro Repair services from our Canadian workshop. We diagnose and repair hashboard, control board, PSU, and fan issues with fast turnaround. See our ASIC Repair Cost Estimator for pricing.
Where to Buy
D-Central stocks the Antminer S21 Pro and ships across Canada and internationally. Buy the Antminer S21 Pro from D-Central — backed by our technical support team, repair services, and full parts inventory including BM1370 chips and cooling accessories.