Since early September, three cases of Bitcoin blocks being found by individual miners have been reported. Each miner mined the cryptocurrency using hardware with varying computing power, meaning their chances of finding the block varied significantly.
A few days ago, a miner mined a block using hardware with a processing power of 61 Ph/s (petahash per second)—that’s roughly the same as 300 modern mining devices. According to calculations on the SoloChance portal, they have a 1 in 16,000 chance of adding a block each time they search for a new block (every 10 minutes).
The odds of another miner finding a block with 200 Th/s (terahash per second) hardware were once every 10 minutes, or 1 in 4.8 million. And late last week, a solo miner added a Bitcoin block to the blockchain using a single device with just 4.8 Th/s. Their odds of success were an incredible 1 in 202 million.
An expert explained to RBC-Crypto how the probability of mining a Bitcoin block is calculated during solo mining, and why this type of mining is closer to gambling than serious business.
As of September 9, 2025, Bitcoin mining difficulty is approximately 136 T (trillion). This record level reflects growing competition on the network: the more computing power miners contribute, the higher the difficulty, keeping the average block time at 10 minutes, explained Anton Gontarev, Commercial Director of Intelion.
For a single miner, this means an extremely low probability of “catching a block,” the expert says. He explains that the mining process is mathematically described by a Poisson distribution: each ASIC miner participates in a kind of “lottery,” where the chance of winning is equal to their share of the global hashrate.
At the current global hashrate, a 200 TH/s device can mine a block on average only once every 90 years. For a 1 TH/s device (approximately five modern devices), the average time drops to 18–19 years, and for a 10 TH/s device, to a year and a half, Gontarev said.
He explained that the probability of an event occurring within a limited period of time can be calculated using the formula, where h is the miner’s hashrate, H is the network hashrate, and 600 seconds is the average interval between blocks:
For example, for a miner with 1 PH/s, the chance of finding a block in a week is about 0.1%, and in a year – 5%. For 10 PH/s, the probability of finding a block in a year already exceeds 40%, the expert noted.
He added that, in practice, solo miners join forces to form services, such as the solo mining pool CKPool, which allows each connected participant to work “solo” but through a shared node. The combined hashrate of such miners is quite high, which is why “success streaks” occur from time to time, as happened this month.
“These examples clearly illustrate the dual nature of solo mining. On the one hand, it’s a lottery with an extremely low chance of success for an individual device. On the other hand, the combined pool of ‘lone miners’ across the network still mines several blocks per month, and the stories of these ‘little winners’ always draw attention to the industry,” says Gontarev.
In the context of solo mining pools, a “single miner” doesn’t mean a miner with a single device; it could also be an entire data center with a large amount of equipment. For example, a miner who mined a block on September 1st using 61 Ph/s rented that power for mining.
The current network difficulty of 136 T makes solo mining more of a gamble than a predictable business, the expert added. However, according to Gontarev, it is precisely this “lottery” nature that creates unique cases where individual enthusiasts receive rewards on par with the largest data centers.
For example, for a miner with 1 PH/s, the chance of finding a block in a week is about 0.1%, and in a year – 5%. For 10 PH/s, the probability of finding a block in a year already exceeds 40%, the expert noted.
He added that, in practice, solo miners join forces to form services, such as the solo mining pool CKPool, which allows each connected participant to work “solo” but through a shared node. The combined hashrate of such miners is quite high, which is why “success streaks” occur from time to time, as happened this month.
“These examples clearly illustrate the dual nature of solo mining. On the one hand, it’s a lottery with an extremely low chance of success for an individual device. On the other hand, the combined pool of ‘lone miners’ across the network still mines several blocks per month, and the stories of these ‘little winners’ always draw attention to the industry,” says Gontarev.
In the context of solo mining pools, a “single miner” doesn’t mean a miner with a single device; it could also be an entire data center with a large amount of equipment. For example, a miner who mined a block on September 1st using 61 Ph/s rented that power for mining.
The current network difficulty of 136 T makes solo mining more of a gamble than a predictable business, the expert added. However, according to Gontarev, it is precisely this “lottery” nature that creates unique cases where individual enthusiasts receive rewards on par with the largest data centers.
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