1. The total quantity of a cryptocurrency's tokens or coins that are publicly available and actively circulating in the open market at a given point in time. Circulating supply excludes tokens that are locked (in vesting contracts, staking protocols, or time-locks), reserved (held by the founding team, treasury, or foundation), or burned (permanently removed from circulation). It represents the actual liquid float available for trading.
2. Circulating supply is the primary input for calculating a token's market capitalization: Market Cap = Circulating Supply × Current Price. It is distinct from Total Supply (all tokens in existence, including locked) and Maximum Supply (the hard cap on tokens that will ever exist). Bitcoin's circulating supply as of 2025 is approximately 19.7 million BTC against a maximum supply of 21 million.
See also: Market Capitalization · Fully Diluted Valuation · Token Vesting