The Bitcoin network has surpassed 20 million BTC mined, blockchain outlet The Crypto Basic reported on March 11.

Blockchain records show the milestone was reached at block height 939,999, and the Foundry USA mining pool completed the mining. That exceeds 95% of Bitcoin's total issuance. The block reward at the time of mining was 3.125 BTC, which is paid to miners who verify transactions and add blocks.

Coinbase CEO Brian Armstrong (브라이언 암스트롱) said, "The 20 millionth bitcoin has been mined," and added that issuing the remaining 1 million coins would take more than a century. Armstrong added that Bitcoin is designed as a decentralised currency system to prevent inflation and operate in the global economy without central control.

Bitcoin's long-term supply structure was designed by Satoshi Nakamoto and its total issuance is capped at 21 million coins. New bitcoins are paid to miners in the form of block rewards, but the amount declines over time.

At the network's launch in 2009, the block reward was 50 BTC, but it is structured to halve every 210,000 blocks. The fourth halving occurred on April 20, 2024, cutting the reward to 3.125 BTC from 6.25 BTC. Miners are therefore generating about 450 BTC a day, about half the level before the halving. The next halving is scheduled for April 11, 2028.

As halvings continue, the pace of Bitcoin supply growth slows. It took 17 years to mine 200,000 BTC, but the remaining 1 million are expected to take far longer. Current projections show satoshis, the smallest unit of Bitcoin, will be issued until 2140, after which block rewards will disappear and miners will receive only transaction fees.

Not all mined bitcoins are actually in circulation. Blockchain records show about 230.09 BTC are permanently unusable. This includes the genesis block reward and bitcoins created with specific scripts. Some users have also lost their private keys, meaning the amount of bitcoin actually available for circulation could be less than the total mined.