Bitcoin has a hard supply cap of 21 million coins, one of the system’s defining traits. According to the source material, about 90% of all bitcoin has already been mined. As of January 2022, nearly 19 million BTC were already in circulation, while the final coin is not expected to be mined until around 2140. That long runway comes from Bitcoin’s halving schedule, which steadily slows new issuance over time.
How new bitcoin enter circulation today
Bitcoin runs on a proof-of-work consensus model, where miners use computing power to add new blocks to the blockchain. In return, they receive two forms of compensation: newly issued bitcoin through the block reward and fees paid by users for on-chain transactions. New bitcoin enter circulation roughly every 10 minutes, which matches the network’s average block time.
The issuance schedule is fixed in the protocol. Every 210,000 blocks, the block reward is cut by 50% in an event known as the halving. The source states that the current reward for mining a new block is 6.25 BTC. This predictable decline is what pushes Bitcoin toward its maximum supply without ever exceeding it.
Once issuance ends, miners would be paid by fees alone
After all 21 million bitcoin have been mined, no new BTC will be created. The network, however, would keep operating. Transactions would still be grouped into blocks and processed by miners, but miner revenue would come from transaction fees rather than block subsidies.
That shift matters because miners are central to Bitcoin’s security model. The source notes that if earning potential drops, some miners could move to other crypto networks. If that happened at scale, Bitcoin could face lower decentralization and reduced security. This is presented as a possible outcome tied to miner incentives, not as something already taking place.
Why on-chain fees may rise as second layers handle more activity
The article argues that if Bitcoin adoption keeps growing over the coming decades, on-chain fees could rise sharply, while many everyday payments move to second-layer systems such as the Lightning Network. Bitcoin’s base layer can only confirm a limited number of transactions every 10 minutes. Block space is scarce. That scarcity is what can turn fee competition into a major revenue source.
Under that setup, users who want direct settlement on the main chain may need to pay more for confirmation. Miners, in turn, could keep earning even without block rewards. Routine payments may be pushed toward second layers instead, leaving the main chain to handle more settlement-focused activity with higher fees attached.
A fee-only system could create new miner incentives
The source also points to a potential side effect: in a world without block rewards, miners could collude in an attempt to extract higher transaction fees. If that occurred, on-chain costs could become extremely high. The piece treats this as an unintended possibility rather than a certainty.
At the same time, it suggests that most Bitcoin users may not be heavily affected if second-layer networks become widely used. In that case, scalable, low-cost, and near-instant transactions could happen off the main chain, reducing the need for most users to interact with Bitcoin’s base layer on a regular basis.
Why the last 10% takes so long to mine
Bitcoin does not approach its supply limit in a straight line. Each halving slows the pace of issuance, which is why the remaining final share of supply takes much longer to mine than the earlier years did. The source says the last bitcoin is expected around 2140, meaning the final 10% of supply stretches across more than a century of gradually shrinking block rewards.
That design leaves Bitcoin with a very long transition from subsidy-driven miner income to a fee-driven model. By the time issuance ends, the economic balance between miners, fee markets, the main chain, and second-layer networks may define how the system continues to function.