Antminer S21 Review 2025: Specs, Profitability & Is It Worth Buying?
Bottom line: The Antminer S21 (200 TH/s) is a solid, affordable air-cooled Bitcoin miner at $2,254. It’s not the most efficient machine Bitmain makes, but it requires no special cooling infrastructure and delivers respectable ROI for small-to-mid farms. Here’s our full analysis.
Antminer S21 Key Specifications
Performance Rating
Profitability Estimate (2025)
At BTC $65,000 and $0.06/kWh electricity cost:
- Daily revenue: ~$10.50
- Daily power cost: ~$5.04 (3,500W × 24h × $0.06)
- Daily net profit: ~$5.46
- Monthly net: ~$164
- Break-even at $2,254: ~14 months
At $0.04/kWh (favorable rates), the break-even shrinks to ~10 months. At $0.10/kWh, the S21 becomes marginal. Power cost is the key variable.
S21 vs S21 XP vs S21 Plus
Many buyers hesitate between the base S21 and its siblings:
- S21 (200 TH/s, $2,254): Best entry price. Higher J/TH than XP but no infrastructure premium.
- S21 XP (270 TH/s, $4,590): 35% more hashrate, 23% better efficiency. Better ROI over time, higher upfront.
- S21 Plus (235 TH/s, $2,199): Only slightly more expensive than base S21, 17.5% more hashrate. Strong value.
If budget allows, the S21 Plus is slightly better value than the base S21. But for first-time buyers wanting to test the water, the base S21 at $2,254 is a legitimate choice.
✅ Pros
- Low entry price ($2,254)
- Standard 220V — no special power
- Easy air-cooled setup
- 365-day warranty
- SPOT shipping in 7 days
- Accepts crypto payments
❌ Cons
- 17.5 J/TH — not the most efficient
- 75 dB noise requires ventilation
- S21 XP offers better ROI long-term
- No hydro option at this tier
The Antminer S21 is a solid, accessible Bitcoin miner. It’s not the flagship — that’s the S21 XP — but it delivers real hashpower with a lower barrier to entry, standard power requirements, and a full 365-day warranty. For first farms or budget-focused operations at favorable electricity rates, it remains a smart buy in 2025.
Related: S21 vs S21 Plus Comparison · Best Bitcoin Miner 2025 · Mining Profitability Guide