Once Bitcoin miners have unlocked all the bitcoins, the planet's supply will be exhausted. Part of what makes Bitcoin valuable is that its supply is limited. Only 21 million bitcoins will ever 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 in the Bitcoin block chain. As a reward for doing this work, the miner who manages to add a block first receives a certain amount of Bitcoins. Since a new block is added to the Bitcoin block chain approximately every 10 minutes, the total number of Bitcoins in circulation is increased by 6.This means that the scarcity of Bitcoin is even greater than that of gold.
Although gold is difficult to mine, there is an almost "infinite" supply as new mines are always being sought. There are 21 million Bitcoins in total, of which almost 17 million are in circulation. The Bitcoin source code determines how many bitcoins are left. After removing all these unreachable coins, bitcoins have just 44 the total number of existing technical bitcoins left.
After 64 total halvings, there will be no more Bitcoins left to reward miners and all 21 million Bitcoins will be in circulation. To compare three of the most popular cryptocurrencies, Bitcoin has a total supply of 21 million, XRP (formerly ripple) has a total supply of 100 billion, but just under half of them are in circulation, and Ethereum (ETH) has no supply limit, with over 110 million already in circulation. In short, the actual amount of Bitcoins in circulation today is much smaller than the total amount of Bitcoin mined. Bitcoin's popularity is linked to the fact that its limit is capped at 21 million bitcoins in total.
This causes new bitcoins to be created more quickly, so that most days more than 900 new bitcoins are created. Between lost, stolen and retained bitcoins, there are only about 8 million bitcoins left in circulation in today's market. Bitcoin, for its part, sought to establish a decentralised form of a 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.