Arithmetic on today's supply, not a forecast. It assumes nothing about whether Bitcoin could attract that much money.
A coin's market capitalisation is its price multiplied by the number of coins in circulation. Bitcoin has 20,055,955 BTC in circulation at $77,303.44 each, which is $1.55T. Holding that supply still and putting Bitcoin Cash's $4.53B in its place gives $225.9347 per BTC.
Bitcoin is already worth more than Bitcoin Cash. Moving to the smaller cap would take BTC down to $225.9347, which is 0.003x of what it trades at now.
Supply is held still, and in practice it moves: coins are minted, burned and unlocked, and every one of those changes the price a given market capitalisation implies. The figure also says nothing about whether the money exists to buy BTC at that level, which is the part that actually decides a price.
$225.9347 per BTC. That is Bitcoin Cash's current market capitalisation of $4.53B divided across the 20,055,955 BTC in circulation.
0.003x. Bitcoin trades at $77,303.44 today and Bitcoin Cash's market cap is $4.53B against Bitcoin's $1.55T.
No. It is one division: Bitcoin Cash's market capitalisation spread over the supply of BTC that exists today. It assumes nothing about whether Bitcoin could attract that much money, and it holds the supply still when in practice supply changes.
It sets it. Market cap is price times circulating supply, so the same $4.53B of market cap spread over more coins gives a lower price per coin. This uses the 20,055,955 BTC in circulation now.