What is a stale share?

A stale share is mining work you submit after the pool has moved on to a newer job. Your device may have done the work correctly, but it arrived too late to count as useful work under the pool’s rules.

What a share proves

When you mine with a pool, you combine your work with other miners. The pool gives your miner a job and asks it to find results that meet a set level of difficulty.

A share is one of those results. It usually is not strong enough to create a Monero block, which is a new batch of transactions added to the network’s record. Instead, it proves that your device has been doing mining work.

The pool uses eligible shares to calculate your part of its rewards. A stale share belongs to an outdated job, so the pool may reject it or treat it differently from a normal accepted share.

Why work becomes stale

Imagine you are answering a question, but the question changes just before you send your answer. Your answer might have been right a moment ago. Now it no longer fits.

That can happen when the Monero network finds a new block. Your pool updates its mining job, but your device may still be finishing or sending work for the previous one.

Monero finds a block roughly every two minutes on average. Blocks do not arrive on a fixed schedule, so a job can change unexpectedly.

Common causes of stale shares include:

• Network delay: The new job takes time to reach your device, or your share takes time to reach the pool.
• An unstable connection: Wi-Fi interruptions or reconnects hold up messages.
• Slow job switching: Your miner keeps working on an old job before starting the replacement.
• Pool-side delays: The pool itself is slow to send updates or process submissions.

A small number of stale shares can happen even when everything is working properly.

Does a stale share earn anything?

That depends on your pool’s payout rules. Many pools do not pay for stale shares. Some may give them partial credit or handle certain late submissions differently.

Check your pool’s explanation of accepted, stale, and rejected shares. Do not assume every pool uses those labels in exactly the same way.

A stale share is also not necessarily an invalid share. An invalid share fails a required check, such as meeting the pool’s requested difficulty. A stale share can meet that difficulty but still arrive for an outdated job.

If your pool gives no credit for stale shares, the electricity and processing time spent producing them do not contribute to your payout.

What you can do about them

Look at your stale rate over several hours, rather than judging it from a few submissions. With only a handful of shares, one stale result can make the percentage look unusually high.

To reduce avoidable stale shares:

• Choose a nearby pool server with a reliable connection.
• Use stable Wi-Fi or a wired connection where practical.
• Keep your miner updated.
• Check whether connection drops match spikes in stale shares.

For browser mining, a paused background tab or a sleeping device can interrupt communication. Check how your browser miner handles these interruptions rather than assuming the pool is at fault.

The bottom line

A stale share is work that missed its useful window. Occasional stale shares are normal, but a persistent rise is worth checking because uncredited shares reduce the work counted toward your rewards.