Max supply is fairly simple. What is the maximum potential supply of this token? For Bitcoin it’s 21,000,000. Ethereum doesn’t have one. For Crypto Raiders we set it at 100,000,000. For Yearn it’s 36,666.
Circulating Sup ply is where things get trickier. How many of a given token are circulating? For Bitcoin it’s easy, just subtract how many haven’t been released from the max supply and you have your number. Other L1s like Ethereum and Solana either self-report it or there are APIs available that monitor it.