Chasing the flush draw

I was playing a $1/$2 game at Full Tilt and I found myself in a very common situation; should I chase the flush draw? I've been reading up on pot odds it's helped me quite some bit so I thought I would share my findings.

The Flush Draw
There are 13 cards of every suit in the deck.

Odds of hitting by the turn:
A♠10♠ 5♠ 7♥ Q♠
9/47 = 19.14% or 4.2:1 odds against

Explanation: 2 ♠ in your hand, 2 ♠ on the board leaves 9 ♠ in the deck. With 47 unseen cards (2 in your hand and 3 on the board) your odds of hitting one of those 9 ♠ are simply 9/47.

Odds of hitting by the river
A♠10♠ 5♠ 7♥ Q♠ J♣
9/46 = 19.56% or 4.1:1 odds against

Explanation: Same as hitting it on the turn only now there are 46 unseen cards in the deck.

Odds of hitting by the turn or river
19.14% + 19.56% = 38.7% or 1.9:1 odds against

Let's look at how these odds affect your decision:
You have A♠10♠ in the dealer position
3 players limp in the pot and you raise the standard 3x the BB to $6.
The SB calls, the BB folds and 1 player calls.
The pot is at $24

The flop comes
5♠ 7♥ Q♠

The SB bets $18
The other player folds

First calculate the pot odds. You need to call $18 to win $42 giving you pot odds of 2.3:1 which is greater than the odds of hitting your flush so you should definitely call and even raise.

Let's assume you just call, you also need to consider your opponent's bet on the turn if you miss the flush. If your opponent called a raise to $6 before the flop, and bet $18 on the flop there's a good chance he'll bet again on the turn especially if he puts you on a ♠ draw and there's no ♠ on the turn. So let's assume he bets out $45 on the turn (3/4 of the pot, same as on the flop).
Now you're looking at a $63 bet to win $42 giving you pot odds of 1.5:1 making it an easy fold.

Let's take a look at an example on the turn

5♠ 7♥ Q♠ J♣

You called the $18 on the flop (the pot is at $60) and now your opponent bets $45. This gives you 1.3:1 pot odds against the 1.9:1 odds of making the flush on the river. Again you need to consider the implied and reverse implied odds here. If you hit the flush on the river your opponent will most likely bet again giving you the right odds to call. Alternatively the revserse implied odds suggest you should fold because if you don't hit you'll have lost an additional $45.

This is a very simplified scenario and doesn't take into consideration several factors that would affect your play in this situation. For example if you know your opponent is a hyper aggressive player and has nothing more than a Q♣ you can easily push him off the hand by making a substantial raise on the turn or the river. Alternatively if he plays very tight you're limiting your outs of raising him out of the hand on the river if you miss the flush because he's most likely holding the nuts.

Don't forget also that this is a heads up situation. In a multiway pot the odds might change in favor of a call and in this case you're holding the nut flush draw with the A♠ but if you were holding Q♠10♠ you might be drawing to a lower flush.

Knowing your outs and calculating pot odds when chasing a draw is a good starting point to determine whether you should call or fold, but unless you have a good read on your opponents it's not going to make a difference to your overall profitability.

You don't necessarily have to memorize every odds, instead just calculate it by dividing the number of unseen cards by your number of outs. For example if you pick up an open ended straight draw on the flop you have 8 outs (4 of each cards to make your straight) divide that by 47, substract 1 and you'll get 4.8:1

To share my experience:

I called the $18 bet on the flop and the $45 bet on the turn because I knew my opponent was a very loose player and often raised with marginal hands. The river came K♠ and he checked. I bet $100 and he raised to $150, I call and he shows Q♥ Q♠.

Welcome to the forum chimaera15
But i am confused....

chimaera15: First calculate the pot odds. You need to call $18 to win $42 giving you pot odds of 2.3:1 which is greater than the odds of hitting your flush so you should definitely call and even raise.

Potodds you need are about 4.1-to-1 ( not considering redraws, implied odds and all that stuff).
The potodds you describe for $18 to win $42 = 2.3-to-1. That is correct. But don't you need 4.1 or more to call?

$18 to win $42 = 2.3-to-1
$18 to win $30 = 1.6-to-1
$18 to win $74 = 4.1-to-1

Don't you need 4.1-to-1 odds to call? So that means the pot have to be like $74?

Correct me if i'm wrong....

Well, it's a little more complicated I'd say.
The biggest thing is, you have implied odds to make up for your lack of pot odds. In no limit holdem you vary rarely have the express odds you need to draw. However your ATs is drawing to a nut flush, a very powerful hand. Assuming your draw comes you will be able to win a very big pot vs a lower flush, sets and two pairs. Sometimes they only have 1 pair, and you can catch and A to beat them. Sometimes you will catch a running straight to win.

So in reality, when they bet $18, you have to realize how much you win WHEN you hit, compared to how much you lose when you miss.

However there is one thing in your analysis that you totally missed. Sometimes they check the turn and you draw for free.

It also seems you misunderstand what reverse implied odds are but i'll save that for another time.

Long story short... more often than not, your nut flush draw will be able to profitably call a bet with 2:1 odds on the flop.

btw lol, the deck you're playing with has two Qs.

Ignoring implied odds (which of course can't be ignored), Han's is right. You have to go by the odds of hitting on the next card. the odds of hitting by the river are irrelevent unless you Or him) are all in (or near all in).

Once you miss on the turn your odds of hitting on the river are the 4:1.

Take a silly example. The pot is 20 and he bets 2 on the flop you are getting 10: 1 so of course you call. Now the pot is 24 you blank off on the turn and he bets 2000 of course you fold.

The important thing is the implied odds, if you are both deep it's right to take the worst of it on the flop and even the turn if you expect a big payoff on the river:

You have to know your players, pot is 10 he bets 10 on the flop you aren't getting right price you should fold. You call anyway. Turn you mis he bets 40 into the 40$ pot, again wrong odds you should fold. You call, river you will hit say 1 in 5 times. 4 times you missed and lost 30 that you shouldnt have put in, if the time you hit he will pay you 200 or so then it was worth it.

Note I just pulled those numbers out of the air the 10 and 20 dollar bad decisions don't really cost you 30 cause sometimes they hit, so they really only cost the difference between the amount you could correctly call if going all in and the amount bet.

but... how do I post the suits?