How To Avoid Bet Sizing Mistakes

Things you will learn:

• What you should think about when deciding how much to bet
• How to choose the right amount to commit to the pot

Some ways of playing poker are so embedded in folklore it seems almost sacrilegious to question them. Take the 'standard' opening raise. It's a popular belief that a player who raises pre-flop should raise to three times the big blind. But to do so regardless of the situation is a mistake, albeit a very common one. In early position it offers the player to your left 3/2 on their money. If they call, the next player gets 5/2 and the next player 7/2 - good enough to call with almost any two cards.

When you open from early position for a standard raise and get a call from another early player, this often triggers the calling reflex in the rest of the table. All of a sudden, you're in a five-way pot in poor position with almost no information about your opponents' hands - an easy situation in which to go broke.

In essence, the standard raise isn't big enough. By making a larger raise in early position you're more likely to thin the field. You're also building a bigger pot with what is probably the best hand, and gaining information about your opponents' possible holdings. If the pot is already large - such as when an ante is in play, people have already limped in or when someone has posted a dead blind or straddle - a standard raise simply offers your opponents excellent pot odds to play. You won't thin the field and, again, you may end up in a large multi-way pot with no idea as to opponents' holdings.

Another problem with the standard raise is that it doesn't take advantage of your ability to manipulate the size of the pot to your advantage. Consider this example: you and your opponent both have $5,000 in a $5/$10 game, you open for a standard raise and the blinds fold, leaving $75 in the pot. Your flop bet will usually be in the $50 to $100 range, but you're probably not going to get your opponent's entire stack on this hand - in fact, you'll be lucky to get $1,000 of it.

However, make it $100 before the flop, there's now $215 in the pot and your typical flop bet will be $150 to $300. You now have a very real shot at your opponent's entire stack simply by risking just $70 more pre-flop. While this is an extreme example, the general point should be clear - don't be afraid to build a big pot when it suits you.

Since the release of Dan Harrington and Bill Robertie's highly-regarded book Harrington on Hold'em, the continuation bet has been very popular with intermediate players. As you all know, the continuation bet is made when you are the pre-flop raiser and is designed to take the pot down when both you and your opponent have missed.

It's a powerful move when used appropriately, which allows you to win a lot of pots that you aren't entitled to, simply because you have shown strength. However, many players misunderstand the theory behind the continuation bet, believing it should always be half the size of the pot. This isn't the case. When Harrington and Robertie suggested the half-pot-sized continuation bet, they did so as a guideline.

They also assumed that such a bet was significant relative to the players' stacks. But in cash games and tournaments with deep stacks, a half-pot-sized continuation bet often isn't big enough to get the job done. If the bet doesn't threaten to take a serious chunk out of their stacks, opponents will often call you with marginal hands such as flush draws or middle pair, hoping to get lucky and bust you. They might even call hoping to bluff you later in the hand - an absolute disaster for you.

Another fundamental error is value betting on the river. For example, let's assume you've made the nuts on the river, there is $500 in the pot, and your opponent has $1,000 left. Many players would make the mistake here of betting around $150. Such a bet is so small relative to the pot that it'll be paid off by almost any decent hand - but it fails to maximise profit in the long run.

To show this, let's compare two possible bet sizes, $150 and $500. Of course, the bigger your bet, the less likely it is to be called, as a typical opponent will need a stronger hand to call a big bet than they will a small bet (although certain players will actually be more suspicious of a big bet and more likely to call).

To illustrate, let's use extreme figures and assume that our $150 bet will be called 90% of the time, while our $500 bet only 40% of the time. The expected value of these bets is simply the probability that we will be called multiplied by the amount of the bet, or 0.9 x $150 = $135 for the first bet, and 0.4 x $500 = $200 for the second. That is, on average, we'll win $135 from our opponent when we make the small bet, but $200 when we make the big bet.

As you can see, though the big bet will be called far less often, it still earns a significantly larger long-run profit. In fact, repeat these calculations with any reasonable figures and you'll find that the big bet is usually the better option, as the chance of an opponent calling doesn't decrease in proportion with the size of the bet.

Of course, the whole situation becomes more complicated when you don't have the nuts on the river. Then, you also have to factor in the probability that your hand will be beaten when you are called. The key to value betting is to find the sweet spot, between betting so much that only a better hand will call, and betting so little that you don't make the maximum profit from the hand. Quite often, you'll find that the best bet is bigger than you might think.

One of the often-cited reasons not to vary the size of your bets is that observant players quickly catch on to what you are doing and can read your hands more accurately. However, the typical player should not take this advice too seriously. If you play small to medium-stakes games on the internet or in local casinos, your typical opponent will not be concentrating completely on the game, nor will they be extraordinarily skilled.

If, however, you're playing in games where the players are observant enough to pick up on what you're doing, don't stop varying your bet sizes to your advantage. Either find a better game or introduce a random element into your play - randomly making your bets larger or smaller, but averaging a size that best suits you.