Cryptocurrencies: Is it possible to estimate price from market cap? I'm looking at a website that figures out the potential price of a coin if it had a certain market cap.
I'm not sure I understand the underlying calculations though.
It's well established that: Market cap = Circulating Supply * Price 
So, if you plug in a market cap value, you'd still need to know the coin's circulating supply to determine its price:  how is it possible to determine the circulating supply of a coin at any given point in time?
The standard definition of market capitalisation is:
Market capitalisation = (number of units in existence)*(price).
Update: VARulle gave a link to the definition they use for “circulating supply”: “The best approximation of the number of coins that are circulating in the market and in the general public’s hands.” They need to eliminate “burned” (destroyed?) coins as well as those that might be lost or sent to unrecoverable addresses.
This is an estimate, and so different sources might get different values. Adjusting market cap in this fashion is not normally done in other asset classes, as people generally want to avoid the use of estimates in discussions.