Will Bitcoin Ever Be Fully Mined?
Many people have a common misconception about Bitcoin mining: they believe that with a total supply of only 21 million coins, it will eventually be fully mined. This statement is not accurate. More rigorously speaking, Bitcoin is mathematically “never fully mined.”
The reason comes from a rule set by Satoshi Nakamoto: every 210,000 blocks produced, the block reward is halved. The initial block reward in 2009 was 50 bitcoins, reduced to 25 in 2012, changed to 12.5 in 2016, 6.25 in 2020, and further down to 3.125 in 2024, after which it will continue to halve.
This does not mean that the rewards will drop to zero directly, but rather it is an infinitely decreasing process. From a mathematical standpoint, this represents a geometric series, where the amount of new bitcoins produced will become smaller and smaller, but will never suddenly become 0. It’s like a glass of water; each time you pour out half, the water decreases but it’s hard to truly empty it.
At the same time, Bitcoin itself has a minimum unit limit, known as “Satoshi” (0.00000001 BTC). When the block reward gets down to just 1 Satoshi, the theoretical halving can no longer be accurately executed, resulting in rewards that approach zero infinitely, but do not actually disappear.
From a time scale perspective, it is generally expected that by around 2140, the issuance of new bitcoins will be negligible, but there will still be an extremely small gap compared to 21 million coins. This is why people often say that the total supply of Bitcoin is “infinitely close to 21 million,” rather than strictly equal to 21 million.
So, if the block rewards are getting smaller, why do miners continue to mine? The answer lies in transaction fees. As block rewards decrease, miners' income will gradually shift from “new coin rewards” to “transaction fees.” In practice, there have been cases where a single block relied mainly on transaction fees for considerable income, indicating that the incentive mechanism for mining does not disappear with halving.
As of now, nearly 20 million bitcoins have been mined, with fewer than 1.3 million new coins remaining, and the release speed will continue to slow down. It is this long-term predictable issuance mechanism written into the code that makes Bitcoin’s scarcity increase over time. It is not that it will suddenly be “fully mined” one day, but rather it will gradually approach a ceiling over a long period of time.
