Updated: Jul 15
Bitcoin is like digital gold in many ways. Like gold, bitcoin cannot simply be created arbitrarily; it requires work to "extract." While gold must be extracted from the physical earth, bitcoin must be "mined" via computational means.
Bitcoin also has a stipulation—set forth in its source code—that it must have a limited and finite supply. For this reason, there will only ever be 21 million bitcoins ever produced. On average, these bitcoins are introduced to the Bitcoin supply at a fixed rate of one block every ten minutes. In addition, the number of bitcoins released in each of these aforementioned blocks is reduced by 50% every four years.
The Supply of Bitcoin Is Limited to 21 Million
In fact, there are only 21 million bitcoins that can be mined in total.1 Once miners have unlocked this number of bitcoins, the supply will be exhausted. However, it's possible that bitcoin's protocol will be changed to allow for a larger supply. What will happen when the global supply of bitcoin reaches its limit? This is the subject of much debate among fans of cryptocurrency.
Currently, around 18.5 million bitcoins have been mined. This leaves less than three million that have yet to be introduced into circulation.
Bitcoin Mining Rewards
The first 18.5 million bitcoins have been mined in the ten years since the initial launch of the Bitcoin network. With only three million more coins to go, it might appear like we are in the final stages of bitcoin mining. This is true but in a limited sense. While it is true that the large majority of bitcoins have already been mined, the timeline is more complicated than that.
The Bitcoin mining process rewards miners with a chunk of bitcoin upon successful verification of a block. This process adapts over time. When bitcoin first launched, the reward was 50 bitcoins. In 2012, it halved to 25 bitcoins. In 2016, it halved again to 12.5 bitcoins. As of February 2021, miners gain 6.25 bitcoins for every new block mined—equal to about $294,168.75 based on February 24, 2021, value. This effectively lowers Bitcoin'