Correctly calculate pot odds

[paulw]

Hi all, I always thought I was calculating my pot odds correctly but am now doubting myself. Can anyone advise the correct way?
Example:
Flop comes and I have a flush draw. 33% chance to hit on turn or river or 2:1.
Lets say pot is $40 and villan bets $20 making the pot $60 and $20 to call.
Now, which is the correct method in analysing if I am getting the right odds?
a) I have to bet $20 which is 33% of the current pot, making it neutral EV, or
b) The odds being offered are 3:1, making it 25% of the pot

I think I have just confused myself here over thinking things so if anyone could clarify that would be great.
Thanks!

[Bona]

Villain made a good bet here.

This is not a good call IMHO. You are getting 3:1 on a 4.2:1 shot. Some might say you have the implied odds of future bets but you also have the reverse implied odds of having to call the turn to see the river card. So I say we can't call more than approximately a $12 dollar bet here. Then recalculate on the turn if you miss.

Now nothing was said about players to your left so I a assuming you are heads up and closing the action. You also haven't mentioned stack sizes, reads, or previous action so I am assuming this hypothetical is just a question about pure odds to draw, you are pretty sure you are behind, your only outs are the flush draw, and a bluff here is out of the question.

[paulw]

How come it is a 4.2:1 shot? There are 2 cards to come, I have 9 outs, so is this not about 35% or so, or 2:1?

EDIT: Ok I see now, 4.2:1 to hit on the turn. So when calculating pot odds in such a scenario, is it best to calculate my odds and outs based on the chances of hitting on the next card only rather than hitting on the turn OR river?

Assume pot is heads up, assume that if I make the flush it is the best hand, that I am currently behind and a flush is the only way to win - i.e 9 outs only. For the purposes of this question, no need to worry about implied odds etc, I am just wondering if in the scenario given how I calculate if a call is going to be +EV or -EV.

[Bona]

Well not exactly. You only see one card for this bet calculation. To see the second card you must assume you will have to call another bet. Or if you are going to fold to a turn bet you couldn't use "two cards to come" as your original calculation.

[Bona]

[ QUOTE ]
EDIT: Ok I see now, 4.2:1 to hit on the turn. So when calculating pot odds in such a scenario, is it best to calculate my odds and outs based on the chances of hitting on the next card only rather than hitting on the turn OR river?


[/ QUOTE ]

Correct

[paulw]

Cool, I see what you mean. I think I just plugged a leak! I guess going on my original assumption, if we're all in on the flop, then I can calculate the odds based on a 33% chance of hitting.

Lets assume then that calling the $20 in the original scenario will end all the betting (i.e. we're all in). I must call $20 into a $60 pot. Is the correct calculation to work out if a call is profitable to say I must bet 33% of the current pot on a ~33% shot (i.e. almost 0EV), or, do I say I am getting 3:1 i.e. 25%, making it clearly +EV?
Apologies if this is really dumb.

[Bona]

Paul your question isn't dumb. I am probably not the best one to address this one though. I mostly play limit, some NL SnG's. If you are primarily a no limit player The recent book by Slansky and Miller; "No Limit Hold'Em Theory and Practice" addresses your questions much better than I can. I think the true answer to your question is "it depends." For example if you are short stacked on purpose and intend to rebuy as needed then I think your assumptions play. However if you lose and you are out, as in an SnG, you might not want to play it this way depending on blind levels, stack sizes, number of players left etc. Sorry I can't do better. Maybe someone will come along with a clearer answer but DO BUY AND USE the book. It is worth its weight in chips.

[paulw]

No worries. Your help is most appreciated, i definitely think I need to add that book to my shopping list.
Thanks again

[benpoker12]

Hey paulw,

Assuming your flush draw will always win the hand and you want to play any +EV hand you have to call this allin. You need 2-1 odds to break even, for example if he would have bet 30 you would lose 30 dollar twice and win 60 dollar once which would make 0 money.

You are getting 60-20, or 3-1 for your money which makes this call profitable. You will lose 20 dollars twice and win 60 dollar once which wins you 20 dollar, thus making your call profitable.

Like Bona said though it depends on situations, maybe in SNG you don't like to take risks like that and wait for a better spot instead of going allin. Also in this example you will always win but there might be times where there's a paired board for example and some of your flush cards might not give you the best hand. You have to keep those in mind and know that you have less outs to win.

[paulw]

Thanks Ben, your post and some further study/math I did has cleared up my confusion.
Now I can analyse some of my hands knowing i'm doing it properly. Thanks again