A supply cap (also called max supply) is the hard limit on the total number of coins or tokens that will ever exist for a cryptocurrency. Once the supply cap is reached, no new tokens can be created.
Notable Supply Caps
Bitcoin: 21 million BTC — the most famous supply cap in crypto.
Litecoin: 84 million LTC.
BNB: 200 million (being reduced to 100 million through quarterly burns).
Cardano: 45 billion ADA.
No Supply Cap
Some cryptocurrencies have no maximum supply. Ethereum has no hard cap but has become periodically deflationary through fee burning. Dogecoin has no supply cap — 10,000 DOGE are minted per minute indefinitely.
Why Supply Caps Matter
A fixed supply cap creates scarcity, which is a core value proposition for assets like Bitcoin ("digital gold"). When evaluating a project, compare the supply cap with the current circulating supply to understand potential inflation. A project with only 10% of tokens in circulation has significant future dilution ahead.