The Bitcoin network has reached a historic stage — 20 million BTC out of the maximum 21 million by the protocol are now in circulation. This means that more than 95% of the total supply of the first cryptocurrency has already been issued. Bitcoin is now entering the slowest phase of its issuance — the mining of the final one million coins.
How the network reached 20 million BTC
In March 9, miners operating under the Proof-of-Work (PoW) algorithm recorded the mining of the twentieth million BTC coin. Thus, less than 5% of the total bitcoin supply cap remains to be issued. After the last bitcoin is mined, the issuance of new coins will cease — a fundamental principle embedded in the protocol.
It is interesting to trace the dynamics of bitcoin issuance:
- The first 10 million BTC were mined in just three years after the network launched in 2009.
- It then took about 14 years to mine the next 10 million bitcoins.
- In total, the journey to 20 million BTC took more than 17 years.
- Half of the maximum bitcoin supply — 10.5 million BTC — was reached back in 2012.
Such a slowdown in bitcoin issuance is due to the programmed reduction in miner rewards and the ongoing increase in network difficulty.
Why is Bitcoin issuance slowing down
Two key mechanisms regulate the rate of bitcoin issuance:
1. Growth of Bitcoin network difficulty
As new miners join the network and the total computational power (hashrate)* increases, the protocol automatically raises mining difficulty. This is necessary to ensure that the average block creation time remains stable — around 10 minutes.
* Hashrate — the total computational power of the Bitcoin network. This metric reflects the total number of hash operations (computational attempts) per second performed by miners to find a new block. It is measured in hashes per second (H/s), and in practice, in terahashes (TH/s), petahashes (PH/s), and exahashes (EH/s).
The mechanism works as follows: approximately every 2,016 blocks (about once every two weeks), the Bitcoin network recalculates the difficulty level. If blocks were found faster than the target time during the previous period, the difficulty increases. If slower, it decreases. In this way, Bitcoin maintains a predetermined issuance pace regardless of the number of network participants.
An increase in Bitcoin network difficulty means that more computational attempts (hashes) are required to find a new block. The higher the total hashrate, the:
- The higher the competition among miners;
- It becomes more expensive to mine one bitcoin.
- The more secure the network is, the less it would require enormous computational resources.
Thus, rising difficulty is both a natural consequence of growing interest in the network and a built-in mechanism for stabilizing its operation.
2. Halving
Thanks to the halving mechanism, the reward miners receive for mining a Bitcoin block is halved every 4 years. In 2009, a miner received 50 BTC per block. With an average block time of around 10 minutes, miners could mine approximately 7,200 BTC per day.
Today, daily issuance stands at about 450 BTC — more than 15 times lower compared to the initial stage.
How long will it take to mine the final one million BTC?
According to estimates, the last bitcoin will be mined around the year 2140. This means that issuing the remaining one million coins will take about 114 years — almost seven times longer than it took to mine the first 20 million.
Even with changes in hashrate and fluctuations in network difficulty, the algorithm automatically maintains the predetermined pace of issuance reduction.
For example:
- In 2032, the reward per mined block will fall below 1 BTC.
- By January 2035, about 99% of all coins will have been mined.
- In 2047, approximately 99.9% of the total supply will be in circulation.
- In 2064, after another halving, the reward will drop to approximately 0.003 BTC (305,176 satoshis*).
* Satoshi — the smallest unit of bitcoin, named after Bitcoin’s creator, Satoshi Nakamoto. 1 satoshi = 0.00000001 BTC (one hundred millionth of a bitcoin).
What will happen after 21 million BTC are mined?
The completion of bitcoin issuance does not mean the network will stop operating. Miners earn income not only from newly issued coins but also from user transaction fees.
As the Bitcoin network grows in popularity, transaction fees may increasingly play a significant role in miners’ revenue structure. Even today, network fees account for a noticeable share of miner profits — approximately $300,000 per day.
Assuming a significant increase in BTC’s price by 2140, mining profitability could be maintained or even increased, even without block rewards. For example, if the bitcoin price rises 100-fold, current fee revenue levels could increase by the same amount in fiat terms.
Is the technological transformation of mining possible?
By the mid-21st century, mining hardware may change dramatically. The industry has already evolved from home CPUs to specialized ASIC devices*, so further evolution appears natural. Potential developments being discussed include:
- quantum computers. Theoretically, quantum computing can significantly accelerate certain mathematical operations. In the context of Bitcoin, discussions focus less on speeding up mining and more on the potential impact on cryptographic algorithms. However, the practical application of quantum machines in PoW mining remains hypothetical: the technology is still far from mass adoption.
- neuromorphic chips. These are processors whose architecture mimics the neural networks of the human brain. Their key advantage is high energy efficiency in performing parallel computations. If such solutions reach industrial maturity, they could reduce mining energy costs and reshape the economics of the crypto industry.
* ASIC devices (Application-Specific Integrated Circuit) are specialized integrated circuits designed to perform a single specific task. In the context of Bitcoin, such devices are built exclusively to compute hashes using the SHA-256 algorithm employed in mining. Unlike general-purpose processors (CPUs) and graphics cards (GPUs), ASICs do not perform a wide range of operations. Still, they significantly outperform them in speed and energy efficiency for this narrow task. As a result, they have become the standard in the mining industry and have almost completely displaced other hardware from bitcoin mining.
Although specific technologies remain a matter of forecasts, one thing is clear: the economic model of the Bitcoin network is designed for long-term existence.