Definition
Pool luck is a metric that compares how many shares a pool was statistically expected to submit before finding a block against how many it actually took. It is usually shown as a percentage: the expected share count divided by the actual share count, times one hundred. A value above 100% means the pool found the block faster than probability predicted (lucky); below 100% means it took longer (unlucky).
A worked example
Suppose a pool, given its share difficulty and the network target, was expected to need about 600,000 shares to find a block but actually found one after 300,000 shares. Its luck for that block is 600,000 / 300,000 = 200%. Over a single block, luck swings wildly; across many blocks it averages toward 100% because block discovery is a memoryless random process driven by raw hash attempts.
Why it matters
Luck directly affects payout timing in reward schemes that distribute only when the pool actually finds blocks. Under those models, an unlucky stretch means thinner payouts even though your hashrate never changed; fixed-rate schemes instead absorb that swing on the operator's side. Understanding luck keeps operators from misreading short-term randomness as a broken miner or a bad pool.
Pool luck is simply mining variance measured at the pool level, and the share counts it depends on are governed by each worker's share difficulty.
See live pool data in the pool centralization tracker.
In Simple Terms
Pool luck is a metric that compares how many shares a pool was statistically expected to submit before finding a block against how many it…