Antminer S21 vs Whatsminer M63S
Side-by-side specs, profitability, and home mining comparison.
Specifications Comparison
| Antminer S21 | Specification | Whatsminer M63S |
|---|---|---|
| 200.0 TH/s | Hashrate | 390.0 TH/s |
| 3,500 W | Power Consumption | 7,215 W |
| 17.5 J/TH | Efficiency | 18.5 J/TH |
| 75 dB | Noise Level | 50 dB |
| 14.6 kg | Weight | 28.0 kg |
| 11,942 BTU/hr | BTU Output | 24,618 BTU/hr |
| 36/100 | Home Mining Score | 44/100 |
| — | Release Year | — |
| SHA-256 | Algorithm | SHA-256 |
| Bitmain | Manufacturer | MicroBT |
Profitability Comparison
Antminer S21
Whatsminer M63S
Based on BTC price of $77,711 and current network difficulty as of May 16, 2026. Actual results vary.
Verdict
Bitmain's flagship S21 versus MicroBT's latest M63S. The two mining hardware giants compete for the title of best current-generation air-cooled Bitcoin miner.
Both are competitive on specs. The S21 benefits from Bitmain's dominant ecosystem — parts, repairs, firmware community, and resale market. The M63S may offer a slight efficiency edge but trails in ecosystem support.
Spec Deltas
Here is every spec where the Antminer S21 and Whatsminer M63S actually differ, with the gap quantified:
- Whatsminer M63S 95% more hashrate (200 vs 390 TH/s)
- Antminer S21 51% better power draw (3,500 vs 7,215 W)
- Antminer S21 5% better efficiency (17.5 vs 18.5 J/TH)
- Whatsminer M63S 33% better noise (75.0 vs 50.0 dB)
- Antminer S21 48% better weight (14.6 vs 28.0 kg)
- Whatsminer M63S 106% more heat output (11,942 vs 24,618 BTU/hr)
- Whatsminer M63S 22% more home mining score (36.0 vs 44.0)
Cost & ROI Over Time
Hardware cost is only half the story — here is how each miner's upfront price plays out against cumulative profit at a $0.10/kWh rate.
| Antminer S21 | Metric | Whatsminer M63S |
|---|---|---|
| $5,500 | Upfront cost (MSRP) | $12,000 |
| -$1.25 | Daily net profit | -$3.37 |
| -$5,955 | Net after 1 year | -$13,230 |
| -$6,411 | Net after 2 years | -$14,459 |
| -$6,866 | Net after 3 years | -$15,689 |
| Does not pay back at current rates (negative daily profit) | Payback period | Does not pay back at current rates (negative daily profit) |
Projections assume continuous operation, a flat $0.10/kWh rate, and no hardware degradation, pool fees, or BTC price change. Real-world ROI varies.
Best For...
Best for Profitability
TieBoth miners produce similar daily profit.
Best for Home Mining
Whatsminer M63SScore: 44/100. 50 dB noise level.
Best for Efficiency
Antminer S2117.5 J/TH — lower electricity cost per terahash.
Frequently Asked Questions
Is the Whatsminer M63S more efficient than the Antminer S21?
The M63S and S21 trade blows on efficiency depending on specific batches and firmware versions. Any efficiency difference is typically within 5%, making ecosystem support and price the deciding factors.
Which manufacturer has better firmware support?
Bitmain's firmware ecosystem is more mature with more third-party options (including D-Central's DCENT_OS for supported models). MicroBT's firmware is reliable but offers fewer customization options.