The Bitmain Antminer S21 represents a generational leap in Bitcoin mining hardware. Built on the BM1368 ASIC chip architecture, the S21 delivers 200 TH/s at just 17.5 J/TH — a significant efficiency improvement over the entire S19 lineup. For home miners and farm operators alike, the S21 strikes a compelling balance between raw hashrate and operational cost.
Released in 2024, the S21 quickly became the baseline for next-generation mining operations. Whether you are upgrading from an S19-series machine or building a new fleet, the S21 sets the standard for what modern SHA-256 mining hardware should deliver.
Antminer S21 Full Specifications
| Specification | Details |
|---|---|
| Manufacturer | Bitmain |
| Model | Antminer S21 |
| Algorithm | SHA-256 |
| Hashrate | 200 TH/s |
| Power Consumption | 3,500W (±5%) |
| Efficiency | 17.5 J/TH |
| Noise Level | 75 dB |
| Weight | 14.6 kg |
| Dimensions | 400 x 195 x 290 mm |
| Operating Temperature | 5-45 °C |
| Cooling | 4 x high-speed fans (air-cooled) |
| ASIC Chip | BM1368 |
| Chip Count | ~330 |
| Input Voltage | 220-277V AC |
| Network Connection | Ethernet (RJ45) |
| Release Date | 2024 |
Performance Analysis
At 17.5 J/TH, the Antminer S21 represents a 40% efficiency improvement over the Antminer S19j Pro (29.5 J/TH) and a 24% improvement over the Antminer S19 XP (21.5 J/TH). Within the S21 family, it sits below the S21 Pro (15 J/TH) and S21 XP (13.5 J/TH) in terms of efficiency, but typically comes at a lower upfront cost.
Compared to the Whatsminer M60S (18.5 J/TH), the S21 holds a slight efficiency edge while delivering higher total hashrate (200 vs. 186 TH/s). For miners focused on maximizing hash per dollar of electricity, the S21 remains one of the most competitive options in its price class.
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 | $4.20 | $126 | Highly profitable — ideal for farm and home operations with cheap power |
| $0.08/kWh | $6.72 | $202 | Profitable — solid margins at average North American rates |
| $0.10/kWh | $8.40 | $252 | Marginal — profitability depends on BTC price; monitor closely |
| $0.12/kWh | $10.08 | $302 | Tight margins — consider dual-purpose heating to offset costs |
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 is purpose-built for rack-mounted farm deployments. At 200 TH/s, it provides excellent hashrate density per unit, and its 17.5 J/TH efficiency keeps operational costs manageable even at scale.
Home Mining (with ventilation): At 75 dB and 3,500W, the S21 is not a quiet machine. However, with proper ducting and a dedicated space (garage, basement, utility room), it can serve as an effective home miner — especially in cold climates where the waste heat offsets heating costs. Pair it with a D-Central cooling shroud to duct exhaust heat into living spaces during winter months.
Dual-Purpose Heating: The S21 outputs approximately 11,942 BTU/h of heat — equivalent to a medium space heater. Canadian and northern-climate miners can offset heating bills significantly by channeling this waste heat through their home. Check out our Bitcoin Space Heater vs Electric Heater comparison for the full economic analysis.
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 include:
- Hashboard failures: Individual hashboards may drop offline due to ASIC chip degradation or thermal cycling. D-Central stocks replacement S21 hashboards.
- Fan errors: Fan speed sensor failures can trigger automatic shutdown. Compatible replacement fans are available.
- Temperature warnings: Ensure ambient temperatures stay within the 5-45 degrees C operating range and that airflow is unobstructed.
- Network connectivity: Ethernet connection drops can be caused by faulty cables or control board issues.
D-Central offers professional Antminer S21 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 and ships across Canada and internationally. Buy the Antminer S21 from D-Central — backed by our technical support team and repair services. We also carry BM1368 replacement chips, replacement hashboards, and cooling accessories for the S21 platform.