You usually won’t be able to read your holdem opponent’s hand accurately enough to know exactly what two cards you’re up against. You’ll have a general idea: "I think she’s probably got a pair of queens, but she also might be slowplaying a set or have a straight draw."

Different strength poker hands will require different bluff sizes to "get the job done." If your holdem opponent has a busted draw, then maybe almost any bet (say a quarter pot-sized bet) will likely be enough to get a fold. If your holdem opponent has a pair, then maybe he’ll call a quarter pot-sized bet, but fold for a two-thirds pot-sized bet. And maybe he won’t fold a set no matter how much you bet.

Finding the right bluff size in Texas Holdem is again a matter of maximizing your expectation. For instance, say you are choosing between two bet sizes: quarter pot-sized and two-thirds pot-sized. (Let’s say the pot is $300, and the candidate bet sizes are $75 and $200.)

You think your holdem opponent has one of three poker hands: a busted draw, a pair, or a set. You think she has a busted draw 30 percent of the time, a pair 60 percent, and a set the other 10 percent.

A $75 bet will get the busted draw to fold 80 percent of the time (you’ll get bluff-raised occasionally) and the pair 20 percent.

A $200 bet will get the busted draw to fold 90 percent of the time and the pair 70 percent. The set will never fold. The expectation of the $75 bet is then $60.

$60=(0.30)[(0.80)($300)+(0.20)(-$75)]+(0.60)[(0.20)($300)+(0.80)(-$75)]+(0.10)(-$75)

The expectation of the $200 bet is $145.

$145=(0.30)[(0.90)($300)+(0.10)(-$200)]+(0.60)[(0.70)($300)+(0.30)(-$200)]+(0.10)(-$200)

Thus, in this example, $200 is the better bluff size. You’re better off trying to get both the busted draws and the pairs to fold rather than just the busted draws.

At the table, obviously you can’t solve equations like this. (And you wouldn’t know the percentages precisely anyway, so even if you could solve equations, it wouldn’t necessarily help you much.) Just think about what hands you think your opponents might have, and what poker hands they might fold for what bet sizes. Choose the size that seems to give you the most benefit for the least risk.

Good luck.

Also recommended:

1. Make Bigger Raises Against Players Who Fold Too Much Postflop
2. Expected Value and Fold Equity Explained
3. Expectation and Multiple Possible Hands
4. An Example of the Play (Bluff on the Turn and River)
5. The Check-Raise Bluff in Texas Holdem