Does Poker Card Counting Work?

Article Updated on June 26, 2023

We've seen it in the movies. A group of maths experts destroys the blackjack tables in a prominent casino, using card counting techniques. The casino has no idea what hit them, they just know that they are losing money, and fast!

What we are really interested in, though, is whether we can use the same techniques at the poker tables and print ourselves a few nice briefcases of United States Dollars. In truth, it's a little different when it comes to online poker, but there are still some useful techniques we can take advantage of.

In poker, card counting is simply one component of a much broader strategy. It isn't used in isolation like it would be at the blackjack tables.

How does it work?

The general concept is identical to blackjack; we want to keep track of which cards remain in the deck, so we can estimate our chances of hitting big on the later streets. The first necessary skill is to be aware of the specific number of cards that can help us.

Imagine that we hold the following hand on the flop texture below -

Take a moment to sit back and think for a minute. Which cards are likely to help us on the turn? Once you have an answer, see if you can count the specific number of cards that would improve our hand.

The first cards that we love are the diamonds. There are 9 of these left in the deck. An Ace may also give us the best hand, and three Aces are remaining in the deck. Indeed, a Five may also give us the best hand in some situations, but it's weak enough that we don't want to rely on it holding up. So, for now, we can calculate that we have 12 good outs.

Speeding up the Process

It may have taken us a little while, the first time we calculated this. This is because we potentially had to individually count every card that can help us. The good news is that there are shortcuts, based on the type of hand we hold.

Memorising this list will help us to avoid spending too much time calculating, in the middle of a hand. This frees us up to think about our opponents and make the best play. But so far we are still missing something. How does knowing the number of outs we have actually help us?

Calculating Pot Equity

Knowing the number of outs we have allows us to establish something more important, how much “poker equity” we have in the pot. Equity is essentially a fancy way of saying how likely it is for us to make our hand and hopefully rake the pot. We can use a simple rule to calculate our equity. “The 2 Times and 4 Times Rule” or “Rule of 4 and 2”.

This rule will work when we are on the flop and turn only, so don't try using it pre-flop or on the river when there are no cards to come.

2 Times and 4 Times Rule (Rule of 4 and 2)

• On the Flop – Multiply the number of outs by 4 to calculate pot equity
• On the Turn – Multiply the number of outs by 2 to calculate pot equity

So, if we return to our previous example where we held the flush draw, we established that we had around 12 outs.

We can estimate our pot equity by multiplying our number of outs (12) by 4 since we are on the flop. This means we have roughly a 48% chance to hit our Ace or Flush by the river. Remember that this is an estimate, and the actual poker calculation is a little more complex. We wouldn't want to spend our time thinking about it during an actual hand. The two and four times rule (Rule of 4 and 2) should be accurate enough to make excellent decisions at the table.

Math in poker – If you really hate maths, you can skip this section. But for those of us that are interested, how exactly does the 2 Times and 4 Times Rule (Rule of 4 and 2) work?

Imagine we are on the turn with 9 outs. There are 46 unknown cards left in the deck. This means the probability of hitting is 9/46. If we imagine there were 50 cards in the deck instead of 46, we can simplify this probability to 9/50 which is the same as saying 18/100 or 18%.

However, the real value of 9/46, when expressed as a percentage, is 19.5% not 18%. In reality, we'd have to multiply our number of outs by 2.174, but who has time for that during an actual hand? We much prefer to make a decent estimate based on easy numbers.

Be Careful of Tainted Outs

Have you ever been in a situation where you make your draw only to lose a whole bunch of chips against a much bigger draw? Sometimes there is nothing we can do about this and it's simply the nature of the game. However, in certain situations, it might be because we did not pay attention to which of our outs were “clean”. What do we mean by this?

Have a look at the following hand and board texture. 

How many outs would you say that we have in this situation? At first glance, it looks like we have a huge amount of outs. We have an open-ended straight draw and a flush draw. This type of hand can be referred to as a “combo-draw”. If we check the chart above we can see that we have a whopping 15 outs that can improve us to a straight or a flush. Two of these outs even improve us to the straight flush!

Let's think for a minute, though. How would we feel if the K♥ rolls off on the turn? We have a flush, so should we simply get all the money in as fast as possible? That could easily be a bad idea since any better heart will have us crushed. Or what if we bink the 9♠? Jam all the money and book the next flight to Vegas? Hardly.....any 10 has us beat here. There is still even a chance that our opponent flopped the flush, leaving us in really bad shape.

The problem we have here is that most of our outs are “tainted”. They can actually get us into trouble when we hit. We are mainly interested in “clean” outs, which means they will give us the best hand super often when we hit. In the above example, something like the 4♥ or 9♥ would be a “clean” out because they give us the straight flush. Although, if the 9♥ falls, the 10♥ makes a higher straight flush possible.

Putting it Together

If this is a new concept to us, it will take a little bit of time before we can implement it effectively. The next step on this particular learning curve is to start thinking about how our pot equity relates to our pot odds. Sometimes we can get away with having relatively little pot equity if we are getting excellent pot odds. Assuming we don't get great pot odds (perhaps our opponent makes a large bet), we will generally need to have more pot equity, for it to be correct for us to continue. If any of this seems difficult at first, don't worry, it will come in time.....you can count on it!

Originally Published on January 1, 2017