How does estimated coins calculated on Coinotron? On 'Cointron' their is wallet table after logged in into the site, how they calculate estimated coins per day, estimated rewards, confirmed rewards and unconfirmed rewards?

How does Coinotron derive this value?
Regarding estimated coins per day, with any coin, the golden rule is:

coins per day = kh/s * coins per block / network difficulty / 50


So for example, if you were mining Dogecoin with 800 kh/s, you would have

coins per day = 800 * 250000 / 1000 / 50 = 4000


This 50 is not really a 50 exactly, but rather 2^32 / (3600 * 24 * 1000), where 2^32 is the expected number of hashes required to find a block at difficulty 1 (i.e. the probability of finding a block is 2^-32), 3600 is the number of seconds per hour, 24 is the number of hours per day, and 1000 is the the number of hashes in a kilohash. It works out to be only about 0.5% off, close enough for an estimate.

Estimated current round rewards is an estimate of how many coins you would get, based on your submitted shares, if a block were found right now. As for confirmed and unconfirmed rewards, mined coins require a lot of confirmations before they can be spent. The reason is that if the block gets orphaned, the mined coins disappear. So before the threshold of confirmations (different for each coin) is met, they are considered unconfirmed and cannot yet be paid out. Confirmed rewards, on the other hand, can be safely paid out.