Circulating Supply

What this measures

This chart tracks the total number of bitcoin issued since the genesis block, mined on January 3, 2009, in millions of BTC. Source: Coin Metrics. Every new block creates bitcoin, paid to the miner who found it as a subsidy. There is no other way new coins come into existence: no presale, no founders’ reserve, no authority able to create more.

Issuance written in advance

The subsidy is cut in half every 210,000 blocks, roughly every 4 years: 50 BTC per block in 2009, then 25 in 2012, 12.5 in 2016, 6.25 in 2020 and 3.125 since April 2024. Half of the 21 million was therefore issued before the first halving in late 2012, and three quarters before the one in 2016. That is what gives the curve its shape: a slope that flattens in steps.

The pace follows blocks, not the calendar. When hashrate grows faster than difficulty can adjust, blocks arrive a little early and issuance gets ahead of schedule. Far ahead of time, a halving date can only be estimated.

Because of rounding to the satoshi, the 21 million cap will never be quite reached, and the last satoshi is expected to be mined around 2140.

Issued does not mean available

“Circulating” is a shorthand: the chart counts coins created, not coins that can still move. Lost coins, which market capitalization still values at the market price, are counted just like the rest.

The cap does not rest on a promise but on verification. Every node checks that the subsidy a miner claims follows the rules, and rejects the block if it does not. In August 2010, a bug allowed more than 184 billion bitcoin to be created in a single transaction. A fixed version of the software was released within hours, and the chain containing those coins was abandoned.

🪙 What Is Bitcoin? The Digital Currency Challenging Gold and Central Banks

No other major asset offers this kind of visibility: no one knows how much gold will be mined over the next 20 years, or how much money central banks will create. With Bitcoin, we know exactly how many coins will exist at any given block height, and roughly when.

Each halving also shrinks the subsidy’s share of block rewards. As issuance approaches zero, Bitcoin’s security will have to be paid for almost entirely by transaction fees, and nothing yet guarantees they will be enough.