MicroBT Whatsminer M21 vs MicroBT Whatsminer M66
Side-by-side specs, profitability, and home mining comparison.
Specifications Comparison
| MicroBT Whatsminer M21 | Specification | MicroBT Whatsminer M66 |
|---|---|---|
| 31.0 TH/s | Hashrate | 238.0 TH/s |
| 1,860 W | Power Consumption | 4,736 W |
| 60.0 J/TH | Efficiency | 19.9 J/TH |
| — | Noise Level | — |
| 7,150.0 kg | Weight | 16.0 kg |
| 6,346 BTU/hr | BTU Output | 16,159 BTU/hr |
| 28/100 | Home Mining Score | 16/100 |
| — | Release Year | — |
| SHA-256 | Algorithm | SHA-256 |
| MicroBT | Manufacturer | MicroBT |
Profitability Comparison
MicroBT Whatsminer M21
MicroBT Whatsminer M66
Based on BTC price of $79,027 and current network difficulty as of May 15, 2026. Actual results vary.
Verdict
Our scoring model gives the nod to the MicroBT Whatsminer M66, which leads on 2 of 4 weighted factors (efficiency, hashrate). The standout gap is 668% more hashrate (31.0 vs 238.0 TH/s) in the MicroBT Whatsminer M66's favour. The MicroBT Whatsminer M21 claws back ground on power consumption and home mining score. Review the detailed specs and profitability calculations above to determine which miner best fits your specific setup.
Spec Deltas
The MicroBT Whatsminer M21 and MicroBT Whatsminer M66 diverge on the metrics below — each gap expressed as a real percentage, not a vague "better":
- MicroBT Whatsminer M66 668% more hashrate (31.0 vs 238.0 TH/s)
- MicroBT Whatsminer M21 61% better power draw (1,860 vs 4,736 W)
- MicroBT Whatsminer M66 67% better efficiency (60.0 vs 19.9 J/TH)
- MicroBT Whatsminer M66 100% better weight (7,150.0 vs 16.0 kg)
- MicroBT Whatsminer M66 155% more heat output (6,346 vs 16,159 BTU/hr)
- MicroBT Whatsminer M21 75% more home mining score (28.0 vs 16.0)
Cost & ROI Over Time
Sticker price versus what the miner actually earns back: the table below projects cumulative net profit at a $0.10/kWh electricity rate.
| MicroBT Whatsminer M21 | Metric | MicroBT Whatsminer M66 |
|---|---|---|
| — | Upfront cost (MSRP) | $3,672 |
| -$3.34 | Daily net profit | -$2.71 |
| -$1,218 | Net after 1 year | -$4,662 |
| -$2,436 | Net after 2 years | -$5,651 |
| -$3,654 | Net after 3 years | -$6,641 |
| — | 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
MicroBT Whatsminer M21Score: 28/100. 0 dB noise level.
Best for Efficiency
MicroBT Whatsminer M6619.9 J/TH — lower electricity cost per terahash.
Frequently Asked Questions
MicroBT Whatsminer M21 vs MicroBT Whatsminer M66: which one earns more per day?
At the current BTC price and a $0.10/kWh electricity rate, the MicroBT Whatsminer M66 is more profitable at $-2.71/day compared to $-3.34/day for the MicroBT Whatsminer M21. Profitability depends heavily on your electricity rate — use the selector above to calculate with your actual costs.
Which is quieter, the MicroBT Whatsminer M21 or MicroBT Whatsminer M66?
Both miners have similar noise levels. Check the specs table above for exact decibel readings.
For mining at home, should I pick the MicroBT Whatsminer M21 or the MicroBT Whatsminer M66?
The MicroBT Whatsminer M21 scores 28/100 on our Home Mining Score (vs 16/100 for the MicroBT Whatsminer M66). This composite score factors in noise, power requirements, heat output, size, and setup ease — all critical for residential mining.
How far apart are the MicroBT Whatsminer M21 and MicroBT Whatsminer M66 on J/TH?
The MicroBT Whatsminer M21 runs at 60.0 J/TH while the MicroBT Whatsminer M66 runs at 19.9 J/TH — a difference of 40.1 J/TH. Lower efficiency means less electricity per terahash of mining power, directly reducing operating costs. In relative terms that is 67% better efficiency (60.0 vs 19.9 J/TH).