GHash.IO is one of the largest Bitcoin mining pools, which entered the mining market in July 2013 and contributes to over 30% of the overall hashing power making it the #1 pool in the Bitcoin network. GHash.IO charges 0% pool fee and provides 24/7 technical support for its users. October 2016, GHash.IO pool officially closed. The team behind GHash.IO offers development of custom-built pools and enterprise mining solution.

The collective value of the bitcoin mined in this pool was over $200 million in its first year. GHash.IO worked in conjunction with CEX.IO bitcoin exchange. Apart from mining bitcoin, GHash.IO hosted a Multipool for mining altcoins, as well as separate pools for mining Litecoin, Dogecoin, Auroracoin and . Altcoin mining options were available for independent miners, while bitcoin mining could also be done in the cloud by purchasing cloud-based mining power on CEX.IO Exchange.


Type Mining Pool
Founded July 1, 2013
Headquarters Netherlands
Rewards Pay Per Last N Shares (PPLNS)


Although the hash rate of GHash.IO differs, on average the company has about 7 PH/s of power.


GHash.IO pool uses PPLNS (Pay per last N shares), a reward scheme, according to which payment is given to shares in a window, starting with the last share submitted and going backwards up to some number N of shares. Shares older than the window are not paid. Shares are hashes, smaller than the target for difficulty of 1 (Usually, pools use such difficulty as the target for share, but technically, any difficulty could be used). Every hash created has a 1 in 232 possibility of being a valid share. In order to get Bitcoins in a more distributed and predictable way, miners use pools. If this is the case, miners are awarded Bitcoins, according to their shares.

Compensated Downtime

The pool’s policy provides compensation for CEX.IO mining hardware. Individual miners are not compensated.

Merged Mining

GHash.IO embodies merged mining of such alternative cryptocurrencies, as NMC (Namecoin), IXC (IXCoin) and DVC (DevCoin). At the moment, users can exchange mined NMC for Bitcoins, Litecoins or reinvest them in more GHS. IXC and DVC stand only for withdrawal to other exchanges or respective wallets.

Market share

In the beginning of January 2014 GHash.IO was very close to reaching 51% of all hashing power creating a serious threat to the Bitcoin network. However, all necessary precautions have been taken to change the course of events in order to maintain stability of the Bitcoin community. In order to eliminate the threat GHash.IO temporarily stopped accepting new independent mining facilities to the Ghash.IO pool.


On April 8, 2014, GHash.IO presented a new script-mining feature, GHash.IO Multipool, which enabled users to mine the most financially rewarding coins at any given moment and benefit from additional settings, such as the conversion and the switch settings. This new feature allowed users to mine new cryptocurrencies and convert them into bitcoins or Litecoins, as well as to set the miner to withdraw from the current job when switching coins. The Multipool-Pro functions on the basis of the proportional reward system — when a given block is mined, the reward is divided up among all workers proportionally according to the size of their share.

51% attack controversy

Due to the popularity of Ghash.IO’s mining pool, many people in the bitcoin community were often worried about the possibility of a 51% attack. This kind of attack occurs when a single miner or mining pool is able to mine multiple bitcoin block rewards in a row. This would be a problem for the bitcoin network, because it hypothetically allows the mining pool to double-spend bitcoins. In July 2014, the GHash.IO mining pool exceeded the 51% threshold, which forced the bitcoin community to discuss the possibility of finding a common solution to this threat.

Since it is currently difficult to develop a long-term solution to this problem, the participants agreed to implement some temporary measures. Accordingly, GHash.IO released a voluntary statement, promising that it will not exceed 39.99% of the overall bitcoin hashrate. Moreover, GHash.IO representatives asked other mining pools to follow their example for the sake of the entire bitcoin community. It also stated that a new committee should be created to act as a watchdog against the 51% problem.This committee would include representatives of the mining pools, bitcoin businesses and other specialists in the field.

The 51% discussion received a broad coverage in the media, as well as other publications focused on cryptocurrency news. ArsTechnica,Bloomberg View, Vice Motherboard, Business Times.

Connection with CEX.IO

GHash.IO and CEX.IO have the same account credentials, and therefore the pool is considered to be the mining side of CEX.IO. The connection between these two platforms allows users to benefit from simultaneous trading and mining. Mining power (GHS) purchased at CEX.IO mine new Bitcoins at GHash.IO pool until GHS are sold by the owner.

Traders on CEX.IO could buy shares of Ghash.IO mining hardware to operate on the Ghash.IO mining pool. This is an innovative form of cloud mining which allows miners to enter and leave the bitcoin mining market quickly, without needing to purchase mining hardware. Although most traders take advantage of these cloud mining features of Ghash.IO, actual mining hardware could also be redeemed through CEX.IO. After GHash.IO closed in 2016, CEX.IO continued operating as a bitcoin exchange.

See Also

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