And there will only be 21 million in the future. Part of what makes Bitcoin valuable is that it has a limited supply. Only 21 million bitcoins will exist, each of which can be divided into 1,000 millibitcoins (mBTC), 1,000,000 microbitcoins (μBTC) or 100,000,000 Satoshis. No more bitcoins can be created, and existing bitcoins cannot be destroyed, only lost.
At the time of writing, there are 18,483,118 Bitcoins, although this number is constantly increasing. New Bitcoins are created through a process called mining, which verifies Bitcoin transactions and adds them to the blocks of the Bitcoin block chain. As a reward for this work, the miner who manages to add a block first receives a certain amount of Bitcoins. Given that a new block is added to the Bitcoin block chain approximately every 10 minutes, the total number of Bitcoins in circulation increases by 6.With only 21 million Bitcoins to exist, this means that there are around 13.After removing all these unreachable coins, bitcoins were left with a mere 44 the total number of existing technical bitcoins.
After 64 total halvings, there will be no more Bitcoins left to reward miners and all 21 million Bitcoins will be in circulation. Bitcoin, for its part, aimed to establish a decentralised form of network in which no single entity could influence the supply of bitcoins, thus creating a supply of bitcoins that would automatically adjust itself through a limited supply and diminishing rewards. Unlike central banks, which can issue their currencies in any volume at their discretion, thus causing inflation, the number of Bitcoins increases at a stable, predictable and periodically decreasing rate. According to a study by the blockchain analysis company Chainalysis, there are about 4 million Bitcoins that have been irretrievably lost.
In addition, many Bitcoin holders, including large ones, prefer not to use their Bitcoins as a means of payment. This means that even if these Bitcoins have not been lost, they cannot be considered to be in circulation. Taking all this into account, the actual amount of Bitcoins in circulation today is much smaller than the total amount of Bitcoins mined. Every four years the number of Bitcoins produced per block (a new block is created every 10 minutes) is halved.
Many bitcoins were lost in the early days of the cryptocurrency, because the owners were not so careful when they were worth only pennies.