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

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.

  • If you ever wanted to know some of the odds and probabilities of Texas hold'em poker, from the chances of flopping a flush (0.8%) or set (12%) to the odds of an overcard coming on the flop when.
  • The probability of being dealt a royal flush is the number of royal flushes divided by the total number of poker hands. We now carry out the division and see that a royal flush is rare indeed. There is only a probability of 4/2,598,960 = 1/649,740 = 0.00015% of being dealt this hand.

After the flop you've seen 4 cards of your suit, and 1 of another suit. This leaves 9 cards of your suit, and 38 of a different suit; your odds of completing your flush on the turn are thus 9/47, or 19.14%. If the turn hasn't completed your flush, your odds of completing it on the river are 9/46, or 19.5%.

Royal

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?

Odds

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.

Odds Of Making A Straight Flush In Texas Holdem

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.

Odds

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?

Straight

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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  • It is a common misconception that flush is more likely to hit. If you also believe that to be the case, then you are wrong. Well, maybe you are right, but it depends on which perspective you look at it. Let me explain.

    As long as you start counting the hand from preflop, then you will hit the straight more often than flush. But if you have a flush draw on flop or turn, then you will hit a flush more often compared to when you have an open-ended straight draw, and you hit a straight.

    There is a reason why flush has a higher ranking in poker than straight. It will hit less often. Look at this chance to win a straight and to hit a flush – from Wikipedia.

    You will hit a flush every 0.20% of the time. So once every 509 hands. While you will hit a straight about 0.40% of the time or once every 255 hands, so you will hit almost 2 straights for every 1 flush that you hit.Table of Contents

    Why is it easier to make a flush than astraight?

    But after all that I have written, why is it easier to hit a flush than a straight?
    Well postflop, if you hold a flush draw, you have more outs to hit the draw than holding the open-ended straight draw and hitting the straight. You will have 9 outs to hit a flush on the flop or turn if you have a flush draw.
    From flop to the river, we have 9 outs twice to hit a flush, which is roughly 38%, from turn to the river we have about 18% (9 outs once). On the other hand, if you hold an open-ended straight draw, you will have only 8 outs to hit it.

    What many people are forgetting is that you will get the flush draw less often than you will open-ended straight draw. Getting a suited hand preflop doesn’t happen super often. You will have a flush draw on the flop only 5.1% of the time.

    One thing that is often neglected is you not accounting in the times when you have a gutshot, and you hit it. It seems it doesn’t happen often, but you will usually have 4 outs to hit a straight, which is around 16% from flop to river. Not something we should forget about. On top of that, there are also some double gutters, which also gives you 8 outs to hit your straight.

    So only looking from the postflop perspective, it can feel that it is easier to hit a flush than a straight, but as I explained, that can often be misleading. Straight will happen more often.

    Let’s say you usually play connectors and therefore your chances to hit your straight draw increase. You would have flopped 8 outs straight draw (either open-ended or a double gutter straight draw) about 10.5% of the time on the flop.

    How often will an opponent flop a flush draw?

    A player will have a flush draw on the flop about 5.1% of the time strictly math speaking and accounting in all the hands. But we know that players don’t play every single hand, and they are more likely to fold more off suited hand than suited hands preflop.

    All this makes an opponent hit a flush draw roughly 10% of the time on the flop.

    Which makes more money: Flush vs. straight?

    As expected, flush will make you more money. In my case, not double the amount, but you will make more money with it. Why not the double, you might wonder? Well, if you have a straight, usually you will be willing to stack off with top straight or second nut straight sometimes 3rd nut straight. But when it comes to flush, you will lose quite some money even if you hold a low flush, and it can be less than 3rd nuts. On top of that, not many players will be willing to stack off with the top two or a set on a possible flush board, while the same players don’t have a problem committing with the same hands on possible straight board.

    All this reduces your winrate by a little. But you, as you can see from my graph, will still make substantially more profit with a flush compared to straight. They are both great hands; it is just that a flush is stronger.

    Now your winrate will, of course, differ a bit. If you have nut flush yo will win more than my 2,000bb/100 hands. If you have a lower flush, then it will be lower. Now sometimes higher flushes will beat us. A scenario of when we hit a flush, and our opponent also hits a flush is not that uncommon, and if you multi table, it will happen on semi-frequent occasions.

    The same goes for a straight. Nut straight will give you the most money of any straight. You will still make decent money with 2nd nut straight, just less.

    Scenarios, where we hit backdoor straight, will be nicely profitable since it will be harder for an opponent to put us on a straight, as there was no apparent straight draw present when we started betting on the flop. If you want to read more about straight backdoor draws, I have this article I have for you.

    What are the odds of getting straight flush?

    Odds of hitting a straight flush is so low that it almost doesn’t make sense to write it in percentages. It is a 0.00139% chance you will hit a straight flush. This is 72,192:1 odds against hitting it. SO only once every 72,000 hands you will hit the second most powerful hand in poker.

    What are the odds of getting a royal flush?

    Hitting a royal flush is even harder than a straight flush. The royal flush is the strongest hand you can get in poker. Your chances of hitting it are 0.000154% of the time, or once every650,000 hands (odds against of 649,740:1 to be precise).

    I have been dealt quite many royal flushes in my poker career, and frankly, hitting one doesn’t feel special anymore. But I remember that when I hit it for the first time, I was ecstatic for some time. That is how rare the royal flush is.

    Does a straight beat a flush?

    Poker hand rankings go from strongest to weakest:

    1. Royal flush
    2. Straight flush
    3. Four of a kind
    4. Full house
    5. Flush
    6. Straight
    7. Three of a kind
    8. Two pair
    9. One pair
    10. No pair (high card)

    You can see that straight doesn’t beat a flush, but it does beat many other hands, making it a powerful hand on right boards. When the board is not paired, and no flush can be present, then if you hold the highest straight, you will have the best hand.

    Texas

    What are the odds of getting pocket aces?

    Chances of being dealt pocket aces are slightly less than 0.5%. Exactly once every 221 hands, you will get the rockets. The number of players on the table doesn’t matter. There are still 52 cards in the deck, no matter how many players are at the table.

    If you wonder how often you can expect to win with AA depending on the number of opponents and different hands you are up against, then read this post.

    What are the odds of an ace flop?

    Odds Of Flopping A Royal Flush In Texas Holdem

    We all know it, that horrible feeling when you hope ace doesn’t show up on the flop, but it seems like it always does. It doesn’t always come. But you will see ace on the flop 42% of the time, which is quite often. But don’t worry on some occasions you will also hit two flushes, sets or straights yourself. That is why pocket kings have around 70% (and not only 58%) to win against Ax.