Poker Probability Flush Draw

Mathematics: Flushes & Straights : Simple Pot Odds : Implied Odds : Reverse Implied Odds

So the probability to get the flush on the turn is: 9 outs / 47 possible cards = 0,19 = 19% 4 to 1. The probability is called odds. In Texas Hold'em, odds are regularly given in the notation 'x to y'. A probability of 19% means that you will hit an out on the next street in about one out of five cases. This is given by '4 to 1'. 3) A backdoor flush draw on the flop, needing runner-runner of the suit on the turn and river, will only get there 4% of the time Flush by river (from flush draw on flop if see both turn and river) 1.9 to 1 (35.0%) Flush on draw after missing turn 4.1 to 1 (19.6%) Flush by river on Backdoor Draw on flop 23 to 1 (4.2%) Starting Hand Example.

1. Table #3 – Poker Odds Chart As you can see in the above table, if you’re holding a flush draw after the flop (9 outs) you have a 19.1% chance of hitting it on the turn or expressed in odds, you’re 4.22-to-1 against. The odds are slightly better from the turn to the river, and much better when you have both cards still to come.
2. . The straight flush section has several variations that can change the odds that are displayed. These are primarily and inside draw or an outside draw. For example if you have 5h, 6h, 7h, 8h there are two ways to make the straight flush - either a 4h or a 9h will do it. However if you have an inside draw you have for example 2d, 3d, 5d, 6d.

Watch SplitSuit's video on Flushes and Flush Draws for 8 hand histories involving strategy on playing flushes in Texas Hold'em.

You are on the flop with a pretty decent flush draw. You have two hearts in your hand and there are another two on the flop.

Unfortunately, some cool cat has made a bet, putting you in a tricky situation where you have to decide whether or not it is in your best interest to call to try and make the flush, or fold and save your money.

This is a prime example of where you are going to take advantage of 'pot odds' to work out whether or not it is worth making the call.

What are pot odds? What about flushes and straights?

Basically, just forget about the name if you haven't heard about it before, there's no need to let it throw you off. Just think of 'pot odds' as the method for finding out whether chasing after a draw (like a flush or straight) is going to be profitable. If you're on your toes, you might have already been able to guess that it is generally better to chase after a draw when the bet is small rather than large, but we'll get to that in a minute...

Pot odds will tell you whether or not to call certain sized bets to try and complete your flush or straight draw.

Why use pot odds?

Because it makes you money, of course.

If you always know whether the best option is to fold or call when you're stuck with a hand like a flush draw, you are going to be saving (and winning) yourself money in the long run. On top of that, pot odds are pretty simple to work out when you get the hang of it, so it will only take a split second to work out if you should call or fold the next time you're in a sticky drawing situation. How nice is that?

How to work out whether or not to call with a flush or straight draw.

Now, this is the meat of the article. But trust me on this one, the 'working-out' part is not as difficult as you might think, so give me a chance to explain it to you before you decide to knock it on the head. So here we go...

Essentially, there are two quick and easy parts to working out pot odds. The first is to work out how likely it is that you will make your flush or straight (or whatever the hell you are chasing after), and the second is to compare the size of the bet that you are facing with the size of the pot. Then we use a little bit of mathematical magic to figure out if we should make the call.

1] Find out how likely it is to complete your draw (e.g. completing a flush draw).

All we have to do for this part is work out how many cards we have not seen, and then figure out how many of these unknown cards could make our draw and how many could not.

We can then put these numbers together to get a pretty useful ratio. So, for example, if we have a diamond flush draw on the flop we can work out...

The maths.

There are 47 cards that we do not know about (52 minus the 2 cards we have and minus the 3 cards on the flop).

• 9 of these unknown cards could complete our flush (13 diamonds in total minus 2 diamonds in our hand and the 2 diamonds on the flop).
• The other 38 cards will not complete our flush (47 unknown cards, minus the helpful 9 cards results in 38 useless ones).
• This gives us a ratio of 38:9, or scaled down... roughly 4:1.

So, at the end of all that nonsense we came out with a ratio of 4:1. This result is a pretty cool ratio, as it tells us that for every 4 times we get a useless card and miss our draw, 1 time will we get a useful card (a diamond) and complete our flush. Now all we need to do is put this figure to good use by comparing it to a similar ratio regarding the size of the bet that we are facing.

After you get your head around working out how many cards will help you and how many won't, the only tricky part is shortening a ratio like 38:9 down to something more manageable like 4:1. However, after you get used to pot odds you will just remember that things like flush draws are around 4:1 odds. To be honest, you won't even need to do this step the majority of the time, because there are very few ratios that you need to remember, so you can pick them off the top of your head and move on to step 2.

2] Compare the size of the bet to the size of the pot.

The title pretty much says it all here. Use your skills from the last step to work out a ratio for the size of the bet in comparison to the size of the pot. Just put the total pot size (our opponent's bet + the original pot) first in the ratio, and the bet size second. Here are a few quick examples for you...

• $20 bet into a $100 pot = 120:20 = 6:1
• $0.25 bet creating a total pot size of $1 = 1:0.25 = 4:1
• $40 bet creating a total pot size of $100 = 100:40 = 2.5:1

That should be enough to give you an idea of how to do the second step. In the interest of this example, I am going to say that our opponent (with a $200 stack) has bet $20 in to a $80 pot, giving us odds of 5:1 ($100:$20). This is going to come in very handy in the next step.

This odds calculation step is very simple, and the only tricky part is getting the big ratios down into more manageable ones. However, this gets a lot easier after a bit of practice, so there's no need to give up just yet if you're not fluent when it comes to working with ratios after the first 5 seconds. Give yourself a chance!

To speed up your pot odds calculations during play, try using the handy (and free) SPOC program.

3] Compare these two ratios.

Now then, we know how likely it is that we are going to complete our draw, and we have worked out our odds from the pot (pot odds, get it? It's just like magic I know.). All we have to do now is put these two ratios side to side and compare them...

• 5:1 pot odds
• 4:1 odds of completing our draw on the next card

The pot odds in this case are bigger than the odds of completing our draw, which means that we will be making more money in the long run for every time we hit according to these odds. Therefore we should CALL because we will win enough to make up for the times that we miss and lose our money.

If that doesn't make total sense, then just stick to these hard and fast rules if it makes things easier:

If your pot odds are bigger than your chances of hitting - CALL
If your pot odds are smaller than your chances of hitting - FOLD

So just think of bigger being better when it comes to pot odds. Furthermore, if you can remember back to the start of the article when we had the idea that calling smaller bets is better, you will be able to work out that small bets give you bigger pot odds - makes sense right? It really comes together quite beautifully after you get your head around it.

What if there are two cards to come?

In this article I have shown you how to work out pot odds for the next card only. However, when you are on the flop there are actually 2 cards to come, so shouldn't you work out the odds for improving to make the best hand over the next 2 cards instead of 1?

No, actually.

Even if there are 2 cards to come (i.e. you're on the flop), you should still only work out the odds of improving your hand for the next card only.

The reason for this is that if you work using odds for improving over two cards, you need to assume that you won't be paying any more money on the turn to see the river. Seeing as you cannot be sure of this (it's quite unlikely in most cases), you should work out your pot odds for the turn and river individually. This will save you from paying more money than you should to complete your draw.

I discuss this important principle in a little more detail on my page about the rule of 2 and 4 for pot odds. It's also one of the mistakes poker players make when using odds.

Note: The only time you use odds for 2 cards to come combined is when your opponent in all-in on the flop. In almost every other case, you take it one card at a time.

Playing flush and straight draws overview.

I really tried hard to keep this article as short as possible, but then again I didn't want to make it vague and hazy so that you had no idea about what was going on. I'm hoping that after your first read-through that you will have a rough idea about how to work out when you should call or fold when on a flush or straight draw, but I am sure that it will take you another look over or two before it really starts to sink in. So I advise that you read over it again at least once.

The best way to get to grips with pot odds is to actually start working them out for yourself and trying them out in an actual game. It is all well and good reading about it and thinking that you know how to use them, but the true knowledge of pot odds comes from getting your hands dirty and putting your mind to work at the poker tables.

It honestly isn't that tough to use pot odds in your game, as it will take less than a session or two before you can use them comfortably during play. So trust me on this one, it is going to be well worth your while to spend a little time learning how to use pot odds, in return for always knowing whether to call or fold when you are on a draw. It will take a load off your mind and put more money in your pocket.

To help you out when it comes to your calculations, take a look at the article on simple pot odds. It should make it all a lot less daunting.

Go back to the sublime Texas Hold'em guide.

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A poker player is drawing if they have a hand that is incomplete and needs further cards to become valuable. The hand itself is called a draw or drawing hand. For example, in seven-card stud, if four of a player's first five cards are all spades, but the hand is otherwise weak, they are drawing to a flush. In contrast, a made hand already has value and does not necessarily need to draw to win. A made starting hand with no help can lose to an inferior starting hand with a favorable draw. If an opponent has a made hand that will beat the player's draw, then the player is drawing dead; even if they make their desired hand, they will lose. Not only draws benefit from additional cards; many made hands can be improved by catching an out — and may have to in order to win.

Outs[edit]

An unseen card that would improve a drawing hand to a likely winner is an out. Playing a drawing hand has a positive expectation if the probability of catching an out is greater than the pot odds offered by the pot.

The probability ${\displaystyle P_1}$ of catching an out with one card to come is:

${\displaystyle P_1=\frac{\mathrm{o}\mathrm{u}\mathrm{t}\mathrm{s}}{\mathrm{u}\mathrm{n}\mathrm{s}\mathrm{e}\mathrm{e}\mathrm{n}\mathrm{c}\mathrm{a}\mathrm{r}\mathrm{d}\mathrm{s}}}$

The probability ${\displaystyle P_2}$ of catching at least one out with two cards to come is:

${\displaystyle P_2=1-\frac{\mathrm{n}\mathrm{o}\mathrm{n}\mathrm{o}\mathrm{u}\mathrm{t}\mathrm{s}}{\mathrm{u}\mathrm{n}\mathrm{s}\mathrm{e}\mathrm{e}\mathrm{n}\mathrm{c}\mathrm{a}\mathrm{r}\mathrm{d}\mathrm{s}}\times \frac{\mathrm{n}\mathrm{o}\mathrm{n}\mathrm{o}\mathrm{u}\mathrm{t}\mathrm{s}-1}{\mathrm{u}\mathrm{n}\mathrm{s}\mathrm{e}\mathrm{e}\mathrm{n}\mathrm{c}\mathrm{a}\mathrm{r}\mathrm{d}\mathrm{s}-1}}$

${\displaystyle \mathrm{n}\mathrm{o}\mathrm{n}\mathrm{o}\mathrm{u}\mathrm{t}\mathrm{s}=\mathrm{u}\mathrm{n}\mathrm{s}\mathrm{e}\mathrm{e}\mathrm{n}\mathrm{c}\mathrm{a}\mathrm{r}\mathrm{d}\mathrm{s}-\mathrm{o}\mathrm{u}\mathrm{t}\mathrm{s}}$

Poker Flush Draw

A dead out is a card that would normally be considered an out for a particular drawing hand, but should be excluded when calculating the probability of catching an out. Outs can be dead for two reasons:

• A dead out may work to improve an opponent's hand to a superior hand. For example, if Ted has a spade flush draw and Alice has an outside straight draw, any spades that complete Alice's straight are dead outs because they would also give Ted a flush.
• A dead out may have already been seen. In some game variations such as stud poker, some of the cards held by each player are seen by all players.

Types of draws[edit]

Flush draw[edit]

A flush draw, or four flush, is a hand with four cards of the same suit that may improve to a flush. For example, K♣ 9♣ 8♣ 5♣ x. A flush draw has nine outs (thirteen cards of the suit less the four already in the hand). If a player has a flush draw in Hold'em, the probability to flush the hand in the end is 34.97 percent if there are two more cards to come, and 19.56 percent (9 live cards divided by 46 unseen cards) if there is only one more card to come.

Outside straight draw[edit]

An outside straight draw, also called up and down, double-ended straight draw or open-ended straight draw, is a hand with four of the five needed cards in sequence (and could be completed on either end) that may improve to a straight. For example, x-9-8-7-6-x. An outside straight draw has eight outs (four cards to complete the top of the straight and four cards to complete the bottom of the straight). Straight draws including an ace are not outside straight draws, because the straight can only be completed on one end (has four outs).

Poker Odds Flush Draw

Inside straight draw[edit]

An inside straight draw, or gutshot draw or belly buster draw, is a hand with four of the five cards needed for a straight, but missing one in the middle. For example, 9-x-7-6-5. An inside straight draw has four outs (four cards to fill the missing internal rank). Because straight draws including an ace only have four outs, they are also considered inside straight draws. For example, A-K-Q-J-x or A-2-3-4-x. The probability of catching an out for an inside straight draw is half that of catching an out for an outside straight draw.

Double inside straight draw[edit]

A double inside straight draw, or double gutshot draw or double belly buster draw can occur when either of two ranks will make a straight, but both are 'inside' draws. For example in 11-card games, 9-x-7-6-5-x-3, or 9-8-x-6-5-x-3-2, or in Texas Hold'em when holding 9-J hole cards on a 7-10-K flop. The probability of catching an out for a double inside straight draw is the same as for an outside straight draw.

Other draws[edit]

Sometimes a made hand needs to draw to a better hand. For example, if a player has two pair or three of a kind, but an opponent has a straight or flush, to win the player must draw an out to improve to a full house (or four of a kind). There are a multitude of potential situations where one hand needs to improve to beat another, but the expected value of most drawing plays can be calculated by counting outs, computing the probability of winning, and comparing the probability of winning to the pot odds.

Backdoor draw[edit]

A backdoor draw, or runner-runner draw, is a drawing hand that needs to catch two outs to win. For example, a hand with three cards of the same suit has a backdoor flush draw because it needs two more cards of the suit. The probability ${\displaystyle P_{rr}}$ of catching two outs with two cards to come is:

${\displaystyle P_{rr}=\frac{\mathrm{o}\mathrm{u}\mathrm{t}\mathrm{s}}{\mathrm{u}\mathrm{n}\mathrm{s}\mathrm{e}\mathrm{e}\mathrm{n}\mathrm{c}\mathrm{a}\mathrm{r}\mathrm{d}\mathrm{s}}\times \frac{\mathrm{o}\mathrm{u}\mathrm{t}\mathrm{s}-1}{\mathrm{u}\mathrm{n}\mathrm{s}\mathrm{e}\mathrm{e}\mathrm{n}\mathrm{c}\mathrm{a}\mathrm{r}\mathrm{d}\mathrm{s}-1}}$

For example, if after the flop in Texas hold 'em, a player has a backdoor flush draw (e.g., three spades), the probability of catching two outs on the turn and river is (10 ÷ 47) × (9 ÷ 46) = 4.16 percent. Backdoor draws are generally unlikely; with 43 unseen cards, it is equally likely to catch two out of seven outs as to catch one out of one. A backdoor outside straight draw (such as J-10-9) is equally likely as a backdoor flush, but any other 3-card straight combination is not worth even one out.

Poker Probability Of Flush

Drawing dead[edit]

A player is said to be drawing dead when the hand he hopes to complete will nonetheless lose to a player who already has a better one. For example, drawing to a straight or flush when the opponent already has a full house. In games with community cards, the term can also refer to a situation where no possible additional community card draws results in a win for a player. (This may be because another player has folded the cards that would complete his hand, his opponent's hand is already stronger than any hand he can possibly draw to or that the card that completes his hand also augments his opponent's.)

See also[edit]

• Poker strategy

References[edit]

1. ^Odds Chart. 'How to play texas holdem poker'. Howtoplaytexasholdempoker.org. Archived from the original on 13 January 2010. Retrieved 22 February 2010.

Poker Probability Flush Drawing

External links[edit]