How do you determine your bet size! A simple explanation of the concept
Table of Contents
What is Bet Size?
Bet size is one of the key elements that largely determines a player’s win rate in poker.
Let’s unravel the basic idea behind bet size, why we need to think about it, and the thought process behind it.
Basic Thinking Behind Bet Size
Firstly, as the act of betting chips is based on the odds against the pot, when considering bet size, it’s common to think about what percentage of the pot you are betting.
For example, betting $20 in a $30 pot is quite different from betting $20 in a $100 pot.
In the former case, it is a bet of 2/3 of the pot, while in the latter, it’s 1/5 of the pot.
The Importance of Considering the Appropriate Bet Size
Why is it necessary to think about bet size in detail? There are several reasons, but let’s discuss two particularly important ones.
Changes in Required Win Rate Due to Bet Size
For instance, if you bet $50 in a $100 pot, what should be the necessary win rate for your opponent to call?
This can be calculated as (the amount needed to call) ÷ (total pot amount if the opponent calls).
In the example above, if the opponent calls, the pot will be $200, and the amount needed to call is $50, so 50 ÷ 200 = 0.25, meaning the opponent needs a 25% win rate to call your bet.
Similarly, for a $100 bet in a $100 pot, the opponent needs a 33.3% win rate to call.
| Your Bet Amount | Necessary Win Rate for Opponent to Call |
|---|---|
| 2 times the pot | 40% |
| Pot size bet | 33.3% |
| 2/3 of the pot | 29% |
| Half of the pot | 25% |
| 1/3 of the pot | 20% |
| 1/4 of the pot | 16.7% |
| 1/5 of the pot | 14.3% |
| Thus, by changing the bet size, you can change the win rate required for your opponent. |
Thought Process When Considering Bet Size
Equity of the Entire Hand Range
If your hand range is overall superior to your opponent’s range, it is common to use a smaller bet size (about 1/3 to 2/5 of the pot).
Flop
Pre-flop, you opened with a 600 raise from CO with A♣K❤ and got a call from BB.
On a K♣J♠4♦ flop, a K-high board is generally favorable for the original raiser, so you’d typically bet 1/3 of the pot.
Conversely, if the opponent’s range includes fairly strong hands, and your overall range advantage is lost, betting frequency decreases, and checking increases.
Strength of Equity in the Value Range
If your range contains many hands that are strong now but likely to be outdrawn on the turn or river, bet sizes tend to be larger.
Flop
Pre-flop, you opened with a 600 raise from CO with A♣K❤ and got a call from BB.
On a K♠J♠4♦ flop, a K-high board typically favors a small bet, but due to the two spades and open-ended straight draws like QT, a larger bet of 2/3 of the pot is appropriate.
Conversely, if your range contains many hands that are strong now and unlikely to be outdrawn, bet sizes tend to be smaller.
Combos of Bluff and Value
The number of bluff and value hand combos in your range is crucial when betting.
The bigger your bet, the higher the win rate your opponent needs to call. That’s why, in GTO, the larger the bet size, the larger the share of bluffs you can include in your betting range (on the river, a pot-sized bet supports roughly 2 value hands for every bluff, and a half-pot bet roughly 3 to 1).
Therefore, when you bet with a range polarized between strong hands and bluffs, you can bet larger and include more bluffs. Conversely, when you bet smaller, you can include fewer bluffs, so your betting range should be mostly value hands.
Position and SPR
SPR and position are also important factors in considering bet size.
Generally, the larger the SPR, the larger the bet size needs to be to maximize expected chip gains, especially with strong hands.
Conversely, with a smaller SPR, bet sizes tend to be smaller.
Also, with a small SPR, you always have to be mindful of commitment to the pot.
Moreover, when in position, you act after seeing your opponent’s action and can realize your equity more easily as you see the turn and river, so you tend to use smaller bet sizes to build the pot gradually. In contrast, out of position, bet sizes tend to be larger to offset the positional disadvantage (to make it harder for the opponent to realize equity and to lower the SPR).
Turn
Pre-flop, you opened with a 600 raise from CO with A♣K♦ and got a call from BB.
On an A♠9❤3♠ flop, you bet 600 with a top hit top kicker and faced a check-raise to 2000 from the opponent, to which you called.
On the 8❤ turn, against the opponent’s check, you went all-in with 1.4 times the pot size, targeting their flush and straight draws.
Specific Examples
CO vs BB in a 2-Bet Pot
Flop
You open K❤J♦ to 2.5BB from the CO and get called by the BB. On the flop, you make top pair with a K kicker.
Your hand is strong for now, but there are many scare cards. For example, a spade could give your opponent a flush, and a 9, 8, or 7 could give them a straight.
If you choose a small bet size, you may give draws the right odds to call, or let hands that float you bluff effectively on later streets.
So in this situation, choose a larger bet of about 3/4 of the pot so your opponent can’t see the turn card cheaply.
SB vs BTN in a 3-Bet Pot
Flop
You 3-bet with J♦ T♦ from the SB in response to a 2.5BB open from the BTN. The BTN called, and the flop brought a gutshot straight draw and a backdoor flush draw.
Since the BTN player only called your pre-flop 3-bet, many of their AA and AK hands would have 4-bet instead, so strong hands like AA, QQ, and AK are much more common in your SB range, giving you a range advantage overall.
Therefore, in this situation, making a small bet of about one-third of the pot can put enough pressure on your opponent.
Summary
This chapter explained the thought process behind deciding bet sizes.
There are several factors to consider when determining bet sizes, and it’s necessary to balance these considerations effectively.
Depending on your bet size, you can take a significant number of chips from your opponent.
While sometimes you may think about bet sizes on a hand-by-hand basis, it’s also important to make a wide range of choices while considering range, board texture, and SPR.
Gradually get used to it.