Calculating odds in Texas Hold’em may seem like a mountain to learn if you’re not a mathematician, but it isn’t as tough as many think. Calculating your outs is as easy as counting the cards that would give you a hand that would beat the current nut hand someone may be holding.

If you hold A, K of hearts, and there are two hearts on the board, you have nine possible outs to make the flush. Some outs are not true outs, as in the situation where an opponent may have two pair, and if your flush card comes it may give an opponent a bigger full house.

You take the number of outs and calculate that number against the number of cards left in the deck. Simply:
Total Outs
Remaining Cards

The remaining cards are always all the cards other than yours and the board, like you were playing alone.