Our analyses thus far have assumed that you always have had the best poker hand, and your holdem opponent always has been drawing (or second-best). In Texas Holdem practice, unless you hold the nuts, you will never be certain that you hold the best hand.

The more likely your holdem opponent is to have you beaten, the less likely you should be to bet at all.

If you are sure you have the best hand, then the trick to bet-sizing is to find the amount that causes your holdem opponents to make the biggest aggregate mistakes (given your poker hand and their possible ranges).

But if you aren’t sure, then betting at all could be a mistake for you. The larger the chance that you’re beaten, the bigger that mistake becomes. As the chance you’re beaten rises, you may be better off just letting your holdem opponent draw.

Checking is usually best if you aren’t the favorite,

You aren’t the favorite as calculated by combining the chances that you are beaten already with the chances you will be outdrawn.

and you act last. If you are out of position, however, sometimes you should make a small bet even if you aren’t the favorite. You do this if you frequently expect your holdem opponent to make a large bet if you check. This sort of "small bet to stop a large one" is called a "blocking bet".

Conclusion

You now have a solid theoretical understanding of how to size your bets in Texas Holdem. As a quick summary, here are the rules we learned:

1. Bet enough so that your holdem opponents can’t call profitably.

2. If your holdem opponents could have one of several draws, and that fact means that you’ll sometimes lose money on the river, bet more to cut down their implied odds.

3. Don’t bet so much with the best hand that you blow your poker opponents out of the pot. You’d prefer they sometimes make a bad call than that they fold every time.

4. Size your bet to maximize your expectation, which is the size of your opponent’s possible mistake times the chance he will make the mistake.

5. If your opponents might have one of several draws, size your bet to maximize your expectation against the total range of hands. Sometimes that will mean letting them draw correctly with strong draws if they’ll also draw incorrectly with weak ones.

6. If your opponent might make a second-best hand that would cause him to lose a lot on the river, keep him in the hand. It’s usually better to make a small bet that gets called than to blow him out of the hand with a big bet.

7. Ignore the number of outs your opponent might have if you think he has a hand that he believes may be better than yours without improvement. In that case, your bet should be much more than what his outs might indicate.

8. Don’t forget that you may not have the best hand. The more likely you are to be behind, the less likely you should bet at all. If you aren’t the favorite, checking is usually best if you act last, but if you are out of position, sometimes you should make a blocking bet instead.

Good luck.

Also recommended:

1. Expectation and Multiple Possible Hands
2. Your Opponent Thinks He May Have the Best Hand
3. When Your Opponent Could Have One of Several Draws
4. Determining the Best Hand in Holdem Poker
5. Determining the Best Poker Hand in Omaha High