Reject Rate

The reject rate is the fraction of shares a mining pool refuses to credit, expressed as a percentage of all shares your miner submits. A low, steady reject rate is healthy; a rising one signals a configuration, connectivity, or hardware problem worth investigating. Rejected shares represent wasted electricity, so operators watch this number closely.

What gets rejected

Rejections fall into a few buckets. The most common is the stale share, submitted after the pool already advanced to a new block. Others include shares below the assigned difficulty target, duplicate shares, and malformed or out-of-range submissions, often caused by a miner that did not apply a difficulty change. A pool will also reject shares from a misconfigured worker or one whose clock or job tracking has drifted.

What is acceptable

For a well-connected miner, a reject rate in the low single digits, often cited around one to two percent, is generally considered normal. Sustained higher values usually trace back to high network latency, an overheating or overclocked board producing bad hashes, or firmware that is slow to react to new jobs. Because some rejects are unavoidable latency artifacts, chasing an absolute zero is unrealistic.

Most of a clean miner's rejects are individual stale shares, and the target your miner must beat for each accepted share is set by the pool's share difficulty.