Max Supply for a cryptocurrency is the total amount of coins that can be issued.
The total supply or circulating supply is the amount of the already issued coins, circulating in the market or being locked in specific addresses.
The total supply for the mineable coins will be achieved in the future and it depends on the rewarding plan of the miners. This is resulting to a much smaller starting circulating supply which is increasing over time with the “emission” rate by the block rewards to the miners.
The total supply for the non-mineable coins is usually available from the very first moment and this way the circulating supply is maximized with the launch of the coin. However there are many PoS non-mineable coins which are not starting with their whole maximum supply available in the market and they are building their circulating supply by a rewarding model which is giving coin rewards to the holders (“stakers”) of the coin for the validation of the transactions.
There is a distorted understanding that leads many people to think that the total supply of a digital coin is necessarily the one and only factor that defines the value of the coin. This is totally wrong. There are many coins with 21 million supply which started with a very high valuation and ended up with a valuation next to zero while there are many coins with super high max supply of many billion coins that were launched with almost zero value and after time they have built a better value than coins which have considerably lower maximum supply.
The most important thing for a coin is the fair launch, its transparency, its rich ecosystem with many use cases and the popularity that it can finally get by building a strong Community that is using it. The maximum supply is just one factor which is playing its role together with all the aforementioned.
It is quite important to note that some projects have intentionally higher maximum supplies in order to form more friendly FIAT exchanging rates with their coin units, achieving this way integer and easy to calculate prices.
One Bitcoin’s weakness is that its high valuation combined with its 21 Million supply is leading to long non-integer prices. For example an item costing $2 is translated to 0.00016 BTC (with a 8000$ to 1 BTC exchange rate). Another succesful cryptocurrency with higher maximum supply could theoretically achieve a much easier pricing exchange rate. For example is much more understandable to say that the same item of $2 in the future costs 10 coins of the Z hypothetical cryptocurrency. This would make some cryptocurrency considerably easier to adopt for everyday spending. This is why some Projects took a different approach by choosing a higher inflation and of course a higher maximum supply in order to fix this pricing issue in the future.
Here are some examples of maximum supplies for some digital coins :
Bitcoin has a 21 million max supply
BitcoinZ has a 21 billion max supply
Digibyte has a 21 billion max supply
Zelcash has a 210 million max supply
Safecoin has a 21 million max supply
Zcash has a 21 million max supply
XRP has 100 billion max supply