Max Supply

Max supply is the maximum number of units of a cryptocurrency that can ever exist, as fixed by the protocol's rules. Once max supply is reached, no new coins can be created. Bitcoin's max supply of 21 million BTC is the most famous example: the issuance schedule is written into the protocol, new coins are released as block rewards that halve roughly every four years, and the last fraction of a bitcoin is projected to be mined around the year 2140.

Max supply is central to the scarcity argument for certain cryptocurrencies. A fixed cap means holders cannot be diluted by unlimited printing, which is why Bitcoin is often compared to gold. But not every asset has one: Ethereum has no max supply, relying instead on low issuance and fee burning to constrain growth, and many tokens are inflationary by design to fund ongoing rewards. For example, a data site will list Bitcoin's max supply as 21 million, while showing a dash or infinity symbol for ETH.

A common misconception is that max supply tokens are automatically better investments; a cap says nothing about demand, and a capped token nobody wants is still worthless. It is also worth distinguishing a genuinely enforced cap from a stated one — a max supply is only as credible as the code and governance behind it, since some projects have changed their token supply rules after launch.