Before you know the major differences between Texas Hold’em and Omaha, you must know the major similarities. They both go through the same phases, a Pre-flop, Flop, Turn and River. Besides, the hand ranking is exactly the same. These two factors make it more natural to understand both game types.
Nevertheless, right at the begining of the game you will see considerable differences between them. When playing Omaha, you will receive a total of 4 cards in the Pre-flop; contrariwise, when playing Texas Hold’em you only get 2 cards in the Pre-flop.
Omaha
Even though you have four cards in hands, you can only use two of them to create the best hand possible. This will give you the opportunity to create plenty of combinations, so this type of poker is naturally more aggressive than the Texas Hold’em type, meaning that it is more likely to have high hands.
From the four cards that you receive, you get to choose two of them to complete the hand with three of the community cards.
Texas Hold’em
When playing Texas Hold’em you will use the two hole cards you have received initially to set the best hand possible with the rest of the three of the community cards on the table.
The difference between the combinations of Texas Hold’em and Omaha is translated into mathematics. In conventional decks in Texas Hold'em, there are 1,326 possible two-card combinations before the Flop. In Omaha since there is a four-card scenario in the Pre-Flop, those numbers expand to 270,725 possible combinations.
Common mistake made by a Texas Hold’em player who is about to play Omaha:
In the Pre-flop of Texas Hold'em, a card combination like a pair of aces is enough for the competitor to be very aggressive in his betting. In Omaha, this is not so impressive, and two aces can be easily beaten.
Getting too excited about a pair of aces in the Pre-flop is a mistake that many players make in the transition from Texas Hold'em to Omaha. Therefore, it is crucial to have an exact sense of the strength of each card combination in Omaha and not get too excited right in the Pre-flop.
Example of Omaha:
As mentioned above, each player is dealt 4 cards initially, but then to form a 5-card combination they will use only two of those 4 cards. In this example they used the Ace to complete a pair of Aces and the Eight to complete another pair. As previously stated, the player must always use 3 community cards (board cards) to form the best possible combination of 5 cards, in this case an Ace, an Eight, and a Jack.