mining pool
A mining pool is a group of miners who combine their computing power and share rewards proportionally. Pools reduce the variance of solo mining, giving participants smaller but more frequent payouts instead of rare large ones.
A mining pool is a cooperative arrangement where multiple miners combine their hash power to improve their collective chances of finding a valid block. Bitcoin mining is probabilistic: any single miner may go long periods without ever winning a block reward, even if their hardware is running continuously. For smaller operators, this variance is financially difficult to manage. By pooling resources, participants receive a share of the reward every time the pool finds a block, proportional to the hash power they contributed. This makes income more predictable even though each individual payout is smaller.
Pools are operated by a coordinator who distributes work to members, collects their results, and handles payouts. Different pools use different payout schemes. In a proportional scheme, rewards are shared based on the number of valid partial solutions each miner submitted during a round. The pay-per-share model pays a fixed amount for each piece of work submitted, regardless of whether the pool actually found a block in that period, which shifts the variance risk to the pool operator. Most modern pools use hybrid schemes designed to balance fairness and payout stability.
Some of the largest mining pools by hash share include Foundry USA, AntPool, and F2Pool, each of which consistently accounts for a significant portion of the total Bitcoin hash rate. The concentration of hash power in a small number of large pools is sometimes discussed as a concern for decentralisation, since a pool operator controls which transactions are included in blocks the pool mines. In practice, individual miners can switch pools freely, and the underlying incentive structure makes it economically irrational for a pool to act against the network's rules.