On Friday 1 April, exactly at 18:21:29 Italian, Block 730002 was extracted in the Bitcoin blockchain; as a reward the network issued the BTC number 19,000,000. The theoretical limit of extractable bitcoins is 21 million, so it might seem that we are now close to completing the operations; in reality, however, due to the way the network is structured it is estimated that it will take around 120 years to mine the remaining 2 million BTC. In short, appointment at 2140.
Bitcoin, one of the first cryptocurrencies to hit the market, is based on principles that can now be considered outdated in that sector, but let’s briefly summarize: the network produces new bitcoins every time a block of transactions is added to its ledger. The blocks are “extracted” by solving a very long series of mathematical calculations; the first user to complete a block is rewarded with a certain amount of BTC (plus related transaction fees).
The blockchain, however, progressively reduces the size of the reward as you go on to mine new blocks: the number of BTCs added to the network (and to the wallet of the user who extracted them) is essentially halved every 210,000 blocks. Blocks are mined roughly every 10 minutes (to clarify: a single block across the entire miner network). In the very early stages of the coin’s life, each block mined guaranteed 50 BTC, today we have already dropped to 6.25 (from May 2020).
The maximum limit of 21 million bitcoins is one of the fundamental conditions imprinted in the source code of the coin by its creator, the mysterious Satoshi Nakamoto. It is an atypical feature in the crypto world, but it is deliberate: Nakamoto’s idea was of basically making a digital version of golda finite resource, which can have a significant influence on its value.
The Bitcoin network reached 18 million coins mined towards the end of 2019: it therefore took about two and a half years to mine an additional million currencies. The first 18 million BTC came in ten years. As the network expands and BTC becomes rarer, it is more difficult to mine – like gold, in fact. The graph above helps visualize this concept.