My Actifit Report Card: September 23 2025

Short answer: Extremely small — practically zero chance of finding a Bitcoin block with a single NerdMiner (regardless of whether it's 4.8 TH/s or smaller USB devices) working alone (solo) within a realistic timeframe.

How I calculate this (short, clear, no magic):

The chance of finding a specific block is approximately:
p = (your miner hashrate) / (total network hashrate). The blockchain produces ~144 blocks/day (≈ 10 minutes per block).

Example NerdMiner models (evidence): a frequently cited model, NerdQaxe++, has ~4.8 TH/s; however, there are also significantly weaker USB variants.

The current network hashrate (example time, source) is approximately 1.107 ZH/s = 1.107 10⁹ TH/s (Zetta → Terra conversion). This is the number in the denominator.

Specific numbers (based on the values ​​above)

I calculated three model examples:

NerdQaxe++ — 4.8 TH/s

Chance per block found ≈ 4.34 10⁻⁹ (i.e., 0.000000434%).

Chance of finding at least 1 block in a day ≈ 0.000062%.

Expected time to find 1 block on average solo: ~1,601,562 days ≈ 4,388 years. (This is a statistical expectation—the variance is high, but it doesn't mean you're guaranteed to have 1 block in 4,388 years; it's just the mean.)

Small USB miner — 0.2 TH/s (200 GH/s)

Chance per block ≈ 1.81 10⁻¹⁰

Chance ≥1 block/day ≈ 0.000003%

Expected days to 1 block solo ≈ 38,437,500 days ≈ 105,308 years.

Tiny miner — 0.00093 TH/s (930 KH/s)

Expected time to 1 block solo: ~22,646,928 years (yes, you read that right).

(I calculated the numbers using the current network hashrate and the miner specs mentioned above — see above for details and sources.)

What this means in practice

Solo mining with such small devices is economically and practically impractical — the probability is vanishingly small.

Pool mining is the realistic option: there you receive regular, small payouts proportional to your hashrate. This increases predictable income (but pay attention to fees and pool rules).

Small bonus calculator (illustrative)

For example, if you operate at 4.8 TH/s, the expected BTC yield is approximately:
~0.00000195 BTC / day → ~0.000712 BTC / year ≈ 71,200 Satoshi/year (based on current network conditions and a 3.125 BTC block reward after the 2024 halving). This is very small — electricity costs and acquisition costs usually make it negatively profitable.

Conclusion (short, honest, motivating)

If you're pursuing this hobby for the fun of technology — great, go for it! 🔧😄
However, if you expect to generate significant income or seriously find blocks solo — forget it and join a pool or invest in larger, more efficient ASICs (but calculate your electricity costs, ROI, etc. first).