Statistical Probability Of Poker Hands

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Main Question or Discussion Point

Hello everyone,
First post here so be kind :)
I am working on a problem, that should be easy, but I just want to make sure my logic is correct. The problem is to find the probability of being dealt event A in a 5 card poker hand, where
A = {2 pair and 1 card all of the same colour}
Now I took a counting approach to this problem, where I counted all the possible ways for A, then divided by 52 choose 5 (the total number of unordered five card poker hands). I tried two ways which seemed to make sense, but they give me different answers.
Method 1
First, choose two ranks: 13 choose 2
Then choose two cards from first rank: 2 choose 2
Then choose two cards from second rank: 2 choose 2
Choose last card in 26-4 ways: 22 choose 1
So P(A) = (13 choose 2)*(2 choose 2)*(2 choose 2)*(22 choose 1)/(52 choose 5) = 0.00066
Method 2
First, choose colour: 2 choose 1
Choose two ranks: 13 choose 2
Then choose two cards from first rank: 2 choose 2
Then choose two cards from second rank: 2 choose 2
Choose last card in 26-4 ways: 22 choose 1
So P(A) = (2 choose 1)*(13 choose 2)*(2 choose 2)*(2 choose 2)*(22 choose 1)/(52 choose 5) = 0.00132
The second probability is obviously two times the first due to the initial choosing of the colour, is this redundant? Which method, if any, is correct?
Thanks for the help.

There is only a probability of 4/2,598,960 = 1/649,740 = 0.00015% of being dealt this hand. Much like very large numbers, a probability that is this small is hard to wrap your head around. One way to put this number in perspective is to ask how long it would take to go through 649,740 poker hands.

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Once you familiarize yourself with basic Texas Hold ‘em play, hand rankings and dealing, you should learn about the odds and probabilities associated with different aspects of the game. While it may be impossible to calculate precise odds mid-hand, particularly given you’ll never see your opponents’ cards until all decisions have been made, knowing when to play (and when not to play) different hands typically requires more than just good instinct.

In Texas Hold ‘em, winners are often decided before the community cards are even laid out, so the chances of being dealt a strong starting hand is something many players think.

Calculating Texas Hold ‘em Odds

To understand the odds of drawing any particular starting hand, you’ll have to consider all of the factors that go into the deal of a hand. Considering a shuffle to completely randomize the order of the cards, the biggest factors that will affect a draw are the number of players at the table and your own position relevant to the dealer. Also consider that there are four cards of any given value in each deck and there are 169 different hole card combinations. That being said, there’s a roughly one in 1326 chance that players will be dealt any specific hand, so it’s important to know what kind of odds you should keep in mind whenever you step to the poker table.

Pre Flop

You have a 55:1 chance of being dealt a pair of Jacks or higher.

Your Texas Hold’em experience will begin with your hole cards, and while you cannot change the cards that are dealt your way, it’s good to know what to expect. While World Series of Poker reruns may make it seem like someone at the table will be dealt pocket kings every hand, starting with a monster hand is rarer than you may imagine. For more on Pre Flop strategy see our guide here.

Quick Odds

While an extensive list of the probabilities for preflop hands could fill a book, here are some quick odds to consider when you’re peeking at your cards for the first time.

  • Being dealt a pocket pair: 16:1
  • Being dealt suited cards: 3.2:1
  • Being dealt suited connectors: 24:1
  • Being dealt AK: 82:1
  • Being dealt two cards of jack or higher: 10:1
  • Being dealt AA, KK, QQ or JJ: 55:1

The Flop

The flop is a game changer in every sense of the words. With more cards in your hand, players will get their first real taste of what the final outcome will look like. That being said, players will want to think about the odds for how their hand could turn out before they start placing or calling bets. For more on Post Flop strategy see our guide here.

Quick Odds

Though the presented odds may be mathematically accurate, they do present a best case scenario that you won’t always find yourself in at the table. These calculations don’t take into account the probabilities of the card or cards you are looking for turning up as burn cards or in your opponents’ hands, so keep that in mind when considering your next move.

  • Hitting a pair on the flop: 2:1
  • Pocket pair improving to three of a kind on the flop: 7:1
  • Flop being three of a kind: 424:1
  • Odds of flopping a flush with suited hole cards: 118:1

The odds of flopping a straight can be a bit harder to pin down. Depending on your starting hand, there are any number of card combinations that could lead to a flopped straight. Those hands that have the more flexibility when it comes to straight draws, particularly middling connectors (those between 5 and 9), have the strongest chances of hitting on the flop because there are more cards that could allow for their straight to hit. The wider the gap between your starting cards, the worse your chances are.

The Turn and River

Naturally, as the hand progresses and fewer cards remain to be dealt, the odds of making any particular hand become slimmer and slimmer. That being said, you’ll want to look at the odds for a hand from beginning to end as well as those from stage to stage.

Calculating Probability Of Poker Hands

Quick Odds

Your odds change as each new card is dealt.

Over the course of a full hand, these scenarios could play out

  • One pair on flop improving to two pair or a set by the river: 4:1
  • Catching an ace on the turn or river: 7:1
  • Open ended straight hitting by the river: 2:1
  • Gutshot straight draw hit by the river: 5:1
  • Pocket pair improving to set by river: 10:1
  • Going runner runner for a flush: 23:1
  • Going runner runner for a straight: 67:1

Poker Probability Formulas

Pot and Implied Odds

In addition to the odds that your cards will pair or better, experienced players know that pot odds, that is, the ratio of the size of the pot to the cost of a call, play an important role in proper Hold’em strategy. With all of the risks that are inherently involved in games like poker, players won’t get far if they don’t decide to gamble every so often – and pot odds allow you to make smarter decision when it comes time to place your money on the line. Pot odds take into consideration the likelihood of making a hand to establish a decent risk vs. reward ratio.

Probability Of A Pair In Poker

Another important statistic for players to keep in mind is ‘implied odds,’ which factor in the likely size and frequency of any betting that may come in later rounds of play. These come into play post flop and will be a factor until the river is dealt, and unlike most other Texas hold ’em odds, implied odds will be entirely based on your read on your opponents’ betting habits and aggression.

Probability Of Poker Hands

To calculate effective pot odds, consider your position in the hand and relative strength, then make a note of the amount of money currently in the pot. If you’re in a position to call, think of how much you stand to win should your hand come out ahead, as establishing a solid return on investment can help turn a questionable call into a big win. If no one has bet, then pot odds can help you deduce what size bet you will want to make in order to shift the statistical probabilities in your favor. With a sound bet, you could either make the continued investment not worth the potential gain or place a value wager designed to elicit a call from any remaining opponents. You will have to decide whether or not your chances of winning are worth risking the amount you could lose if you are wrong – a fine line for some players, but one that must be crossed often. For more on Texas Hold’em pot size and strategy see our guide here.

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