Bet sizing

Before we get into specifics about how to play in certain situations after the flop in no-limit hold’em, we have to look at betting theory in general. Here is the most important thing about betting post-flop: all bets must have a purpose.

That may sound obvious, but be honest with yourself and see if you can convincingly tell me the purpose of most of the bets you make. Generally, there are three things you want to accomplish with a post-flop bet: make them fold; make them call; get information.

If you’re trying to get your opponent to fold, it’s usually because you have a bad hand and want to pick the pot up right there. The average player will make a big bet to scare their opponents off. But this is where a lot of bad all-ins occur. Making a big bet is generally never the right choice here.

Our purpose is to cause our opponent to fold by making a bet that will make him think we have a good hand. But, when we don’t have anything ourselves, getting called is a disaster. This means when you are bluffing post-flop, you want to bet the smallest amount that will still accomplish your goal of getting your opponent to fold.

On the flip side, when you want your opponent to call, you want to bet the largest amount that you think they will call with. Interestingly enough, the amount you come up with for a situation where you want a call is often the same as the amount when you want a fold. This brings up a point I will hammer home throughout this whole series: you should never purposely mix up your play in no-limit hold’em.

Whenever you choose to mix it up, you are choosing a lower equity line of play in order to confuse your opponents and pick up some equity later. But if you play properly – and bet purposefully all the time – you will never need to make a second-best choice in order to mix it up.

The conceptual reason for making a particular bet can be very different, depending on your hand, so your play will appear mixed up to your opponents. What you will see over and over again is that you often come up with the same answer for a bet size when you have a good hand and when you are bluffing.

When looking to get information, logically, we want to pay the least amount for it, so your bet should be large enough that your opponent’s reaction will be meaningful. However – at the same time – you need to keep it small enough to ensure you are paying the minimum for the information needed. An information bet will often look like a bluffing bet, since we want to bet on the small end of the spectrum here. A value bet might look like bluffing and information bets if we think our opponent will only call a small amount.

BET SIZING

From now on I will be talking about small bets as half pot-size bets, medium sized bets as 3/4 pot-sized bets and large bets as pot-sized bets. But what is the right amount to bet? In general, you want to be betting somewhere between half and all of the pot after the flop (excluding the river which is one place where an extra small bet makes sense sometimes).

From a psychological standpoint, opponents generally react about the same to a half pot-sized bet as a whole pot- sized bet. In fact, if anything, opponents will often read the half pot-sized bet as stronger since it is still large enough to be meaningful to them, but it looks more like you are inviting a call – which is scarier. Given that opponents will react the same to those two bets, why would you ever bet towards the whole pot if you are trying to get a fold or just information?

UNDERBETTING THE POT – If we bet below half the pot on the flop or turn, we are making two mistakes; one from a game theory standpoint and the other from a mathematical standpoint. In regards to game theory, we need our bets to have meaning to our opponents.

When we bet below half the pot, the range of hands our opponent is willing to call with becomes quite large. Opponents who might have folded a hand like bottom pair to a larger bet will call to a super small bet. Making a larger bet – at least half the pot – will narrow that range down more effectively. It will cause your opponent to be more selective when calling. This is a good thing. In general, the line is half the pot.

With regards to a mathematical standpoint, whenever you bet, you are setting a pricing situation for both yourself and your opponent. Granted, the smaller the bet, the better the price you set for yourself. But, when we go too low, we offer our opponent too good a price.

Let’s say you bet 1/4 of the pot. There is $1,000 in the pot and you bet $250. When the decision goes back to your opponent there is now $1,250 in the pot for him to call $250. He is getting 5/1. Now 5/1 is a pretty good price on most hands he could be calling with. As an example, if you have top pair and he has bottom pair, he has five outs to win – or a 20% chance with two cards to come. That means your opponent is a 4/1 dog.

If you bet 1/4 of the pot here, you actually offered your opponent a good mathematical proposition, which is a disaster. You allowed your opponent to do good maths.

The bigger disaster comes if your opponent calls a larger bet, say 1/2 the pot or more in this case. With the same $1k pot if you bet 1/2, you are sending the pot of $1,500 back for him to call $500. Now the same opponent is getting only 3/1 on that same 4/1 shot.

If your opponent wants to play, then you have made him pay to suck out on you. You have forced him to do bad maths. Most of the time a half pot-sized bet will offer bad maths to most hands that are drawing against you – even flush draws and straight draws – since they are generally only going to see one more card.

You are in good shape when you can make an opponent pay for his loose play. You never want to offer an opponent a good price on a hand when that opponent would have happily taken a bad price. If you do and your opponent sucks out on you, don’t come complaining to me, because it is your fault!

OVER-BETTING THE POT – Why should you never go above the whole pot? Because you never want to be laying a price on the pot. Let’s say you’re bluffing and you bet half the pot. You are giving yourself 2/1 that your play will work, which means that for the bluff to be profitable, you only need to win the pot a little over 33% of the time. That is a low-pressure play.

But what if you are bluffing and you overbet the pot? Let’s say there is $1k in the pot and you bet $1,500. Now you are laying 3/2 on the pot, meaning in order to be profitable on the bluff you need to win over 60% of the time. Which mathematical proposition do you want?

What is even worse is that opponents who have nothing and are going to fold anyway will usually fold for the half pot-size bet as well as the overbet. So you are putting unnecessary mathematical pressure on yourself, forcing a higher success rate on the bluff for no reason.

EXCEPTIONS – In tournaments in particular, stack size demands a different sized bet. Your stack is only as big as either the chips you have or the chips your opponent has. In the case where an appropriate bet is already somewhere around half the smallest stack, then you should generally go ahead and bet the whole thing. This is because either you are pot committed with the bet or your opponent is.

If you are pot committed with your bet, go ahead and shove all-in. You can’t mathematically fold once you have bet over half your stack anyway. If you have any outs you might as well just put it all-in and go to the river.

The only time you might bet half your stack would be if you’re begging for a call. But even in this case, half stack bets often raise suspicions and a full stack size bet is more likely to get a call. This all holds true if it is your opponent’s stack that’s small. If the right bet is over half his stack, go ahead and put him all-in, even if that means betting more than the pot. Mathematically, it doesn’t make much sense to do otherwise.