Antminer S21 Hydro vs Bitmain Antminer S9 Hydro (18Th)
Side-by-side specs, profitability, and home mining comparison.
Specifications Comparison
| Antminer S21 Hydro | Specification | Bitmain Antminer S9 Hydro (18Th) |
|---|---|---|
| 335.0 TH/s | Hashrate | 18.0 TH/s |
| 5,360 W | Power Consumption | 1,728 W |
| 16.0 J/TH | Efficiency | 96.0 J/TH |
| 50 dB | Noise Level | — |
| 15.8 kg | Weight | 5,150.0 kg |
| 18,288 BTU/hr | BTU Output | 5,896 BTU/hr |
| 44/100 | Home Mining Score | 28/100 |
| — | Release Year | — |
| SHA-256 | Algorithm | SHA-256 |
| Bitmain | Manufacturer | Bitmain |
Profitability Comparison
Antminer S21 Hydro
Bitmain Antminer S9 Hydro (18Th)
Based on BTC price of $77,338 and current network difficulty as of Apr 25, 2026. Actual results vary.
Verdict
Based on our multi-factor analysis, the Antminer S21 Hydro wins on 4 of 5 factors (efficiency, hashrate, home mining score, noise level). The Bitmain Antminer S9 Hydro (18Th) holds the edge in power consumption. Review the detailed specs and profitability calculations above to determine which miner best fits your specific setup.
Best For...
Best for Profitability
TieBoth miners produce similar daily profit.
Best for Home Mining
Antminer S21 HydroScore: 44/100. 50 dB noise level.
Best for Efficiency
Antminer S21 Hydro16.0 J/TH — lower electricity cost per terahash.
Frequently Asked Questions
Is the Antminer S21 Hydro or Bitmain Antminer S9 Hydro (18Th) more profitable?
At the current BTC price and a $0.10/kWh electricity rate, the Antminer S21 Hydro is more profitable at $-0.85/day compared to $-3.50/day for the Bitmain Antminer S9 Hydro (18Th). Profitability depends heavily on your electricity rate — use the selector above to calculate with your actual costs.
Which is quieter, the Antminer S21 Hydro or Bitmain Antminer S9 Hydro (18Th)?
The Antminer S21 Hydro is quieter at 50 dB compared to the Bitmain Antminer S9 Hydro (18Th) at 0 dB. For home mining, lower noise levels make a significant difference in livability.
Which is better for home mining, the Antminer S21 Hydro or Bitmain Antminer S9 Hydro (18Th)?
The Antminer S21 Hydro scores 44/100 on our Home Mining Score (vs 28/100 for the Bitmain Antminer S9 Hydro (18Th)). This composite score factors in noise, power requirements, heat output, size, and setup ease — all critical for residential mining.
What is the efficiency difference between Antminer S21 Hydro and Bitmain Antminer S9 Hydro (18Th)?
The Antminer S21 Hydro runs at 16.0 J/TH while the Bitmain Antminer S9 Hydro (18Th) runs at 96.0 J/TH — a difference of 80.0 J/TH. Lower efficiency means less electricity per terahash of mining power, directly reducing operating costs.