The Bitcoin Halving Schedule

At the core of Bitcoin’s identity as "digital gold" is its pre-programmed, predictable scarcity. Unlike fiat currencies (like the US Dollar or Euro), which central banks can print in unlimited quantities at will, Bitcoin’s monetary policy is locked in stone.

There will only ever be 21,000,000 bitcoins created. The mechanism that enforces this hard cap is the Bitcoin Halving.

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📉 How New Bitcoins Are Born: The Block Subsidy

Bitcoins are not created out of thin air by a company. They are minted through the Block Subsidy—the amount of fresh, newly created bitcoin awarded to the miner who successfully solves a block. This subsidy is packaged inside a special transaction called the Coinbase Transaction, which is the very first transaction in every block.

To distribute these coins over time and ensure that Bitcoin remains deflationary, Satoshi Nakamoto programmed a mathematical decay function into the protocol:

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📅 The Historical Halving Timeline

Here is the exact progression of Bitcoin's supply issuance from its inception:

Era	Block Range	Date	Subsidy per Block	Annual Issuance
Era 1	0 to 209,999	Jan 2009 – Nov 2012	50 BTC	2,628,000 BTC
Era 2	210,000 to 419,999	Nov 2012 – Jul 2016	25 BTC	1,314,000 BTC
Era 3	420,000 to 629,999	Jul 2016 – May 2020	12.5 BTC	657,000 BTC
Era 4	630,000 to 839,999	May 2020 – Apr 2024	6.25 BTC	328,500 BTC
Era 5	840,000 to 1,049,999	Apr 2024 – ~2028	3.125 BTC	164,250 BTC
...	...	...	...	...
Era 33	6,720,000+	~Year 2140	0 BTC (1 sat to 0)	0 BTC

By the year 2140, at Block 6,930,000, the subsidy will drop below 1 satoshi (the smallest unit, $10^{-8}$ BTC) and cannot be divided further. At that exact point, all 20,999,999.9769 BTC will have been minted, and the block subsidy will end forever.

BTC Supply Curve
   21M ├─────────────────────────────────────────── (Hard Cap reached in 2140)
       │                                     .────'
       │                              .────''
       │                       .────''
       │                .────''
       │          .───''
       │     .──''
       │  .─'
    0M └─┴────┴────┴────┴────┴────┴────┴────┴────┴─
        2009 2012 2016 2020 2024 2028 2032 2036 ...

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💸 The Shift to Transaction Fees: How Miners Survive

If the block subsidy is cut in half every four years and eventually drops to zero, why would miners keep running expensive rigs in the future? Won't the network collapse when miners stop working?

No. The protocol’s economic game theory accounts for this transition beautifully.

A miner's total revenue consists of two components: $$\text{Miner Revenue} = \text{Block Subsidy} + \text{Transaction Fees}$$

As the block subsidy declines toward zero, transaction fees must rise to take its place:

1. Increased Block Space Value: As Bitcoin adoption increases globally, more users compete to get their transactions into the limited 1MB/4MB block space. This competition drives up fee rates (measured in sats/vByte).
2. The Pure Fee Era: Once the block subsidy reaches zero in 2140, miners will be funded 100% by transaction fees.

Even today, we occasionally see blocks where the aggregate transaction fees paid by users exceed the 3.125 BTC subsidy. In a mature global network, transaction fees alone will represent a multi-million dollar reward per block, keeping the hashrate high, miners profitable, and the blockchain completely secure without any currency inflation.