"The market cap metric has always been a bit of a weird one for me because there are so many different ways to measure it in the crypto space. The 2 main ways it is measured is via circulating market cap and fully diluted value (FDV). The circulating market cap is simply a calculation of how many coins are in circulation multiplied by the current price whereas the FDV is calculated by taking the total coins that will exist (circulating or not) and multiplying it by the current price. Though neither of these 2 measures actually paint the full picture and they skip most of the nuance entirely. The clearest example here is Filecoin which currently has an enormous $340 billion FDV (larger than Ethereum!) but this figure is not at all accurate.
There have been many attempts at creating better ways to measure a crypto-assets market cap and one that I personally like is called the ‘liquid market cap’ which was created by the Messari team. The liquid market cap is calculated by taking the ‘liquid supply’ of an asset and multiplying it by its current price. Messari defines liquid supply as “the number of units that currently exist on-chain and which are not known to be encumbered by any contracts.” Of course, coming up with an accurate figure using this methodology is still difficult so the liquid supply metric is imperfect but I believe it’s probably a better one to look at than the others."