Coin Mining: What Is an 'Accepted Share'?

In cryptocoin mining, 'accepted shares' has a special meaning

Bitcoin representation in copper coin


Once you're ready to start mining for cryptocoins, you'll start learning about shares. 'Accepted Shares' and 'Rejected Shares' represent scorekeeping in your mining software. Shares describe how much work your computer is contributing to the mining group.

Why Do Accepted Shares Matter?

More accepted shares are good; it means your work is counting substantially towards discovering new cryptocoins. The more accepted shares you contribute, the more pool payout for each coin block that is found. Ideally, you want 100 percent of your shares accepted because that means that every single computation on your computer is counted towards a coin discovery.

What Are Rejected Shares?

Rejected shares are bad, as they represent work that will not be applied toward a blockchain discovery, and they will not be paid for. Rejected shares typically occur when your computer was busy grinding a cryptocoin share problem, and it did not submit the results in time to be counted towards a coin discovery. Rejected share work is discarded.

Keep in mind, though, that rejected shares are inevitable, especially in any mining pool with more than a dozen users. It's just a fact of cryptocoin mining

Very serious coin miners will tweak their GPU (graphics processing unit) settings to maximize how often their computer submits work every second. 

How Cryptocoin Mining Works

Most cryptocoin mining is all about solving mathematical problems, which in turn act as raffle tickets. Each problem solved is called a 'proof of work' result, and counts as one raffle ticket. Every time a predetermined quantity of proof-of-work results is generated, the system draws a raffle number, and one proof-of-work result is awarded a block of new cryptocoins

Every miner who contributed to solving that particular block will get some kind of proportionate share of the rewards. Without accepted shares, then, a miner gets nothing.

It's All About Contributing Your Computer Power to the Mining Group

Because proof-of-work problems are very difficult to solve, results are best achieved when users combine their computers into a 'pool,' with each person's computer contributing a share of the effort.  

As your personal machine achieves its proof-of-work results, it submits its results to the group. The faster you can solve proof-of-work problems, the more results you can submit to the group every minute. If your machine submits its results before the new coin block is found, we call that an 'accepted share.' When the group of people is rewarded with newly minted coins, it distributes those earnings across people proportionately by their accepted shares.

How Rejected Shares Work

If your computer successfully performs work but submits it too late for that block, it is called a 'rejected share' of work. You will get no credit for that work, and it cannot be banked towards future coin discoveries.

Rejected shares are inevitable, regardless of how powerful your mining computer is. The desired goal is to minimize rejected shares and maximize accepted shares.

So, this is a key part of the secret to being a successful cryptocoin miner: you need a powerful machine that can submit many proof-of-work shares before each new coin is found.