What Is a “Stale Share” and How Does It Affect a Miner’s Reward in a Pool?

A stale share is a valid share of work submitted by a miner to the pool that arrives after the pool has already found and submitted a valid block, or after another miner has found a block and the pool is already working on the next one. Stale shares are rejected by the pool and do not contribute to the miner's reward.

High latency or a slow internet connection can increase the number of stale shares, reducing the miner's effective hash rate and profitability.