Max supply is the absolute maximum number of coins or tokens that will ever exist for a cryptocurrency according to its protocol rules. This hard cap creates scarcity, similar to precious metals, and is written into the blockchain's code. Some cryptocurrencies have a fixed max supply, while others have no cap and can produce coins indefinitely. Max supply is a fundamental factor in tokenomics and long-term value propositions.
Example:
Bitcoin has a max supply of exactly 21 million BTC, with the final coin expected to be mined around the year 2140. This means no more than 21 million Bitcoin will ever exist, creating inherent scarcity. In contrast, Ethereum has no max supply so new ETH is continuously created through staking rewards, though annual issuance rates are controlled.