# Four to a flush with suited hand and two community cards, opponent raises, what to do?

I had two suited hole cards in a nine-handed cash game, 50 chips entrance.

The flop opened up with two more cards of the same suit, meaning I had four cards to a flush. My opponent raised six on the flop and I called.

The turn card came down without my suit. My opponent raised another 10, so I folded.

Did I do the right thing? How do you calculate odds for a "four to a flush" situation?

• Happened in a 9 players cash table, 50 chips entrance, opponent raised by 6 chips in flop, i called. Commented Dec 20, 2015 at 16:04
• If you add the exact amounts of the pot and the bets I can also calculate your pot odds in my answer to evaluate if you should have called. But I believe that with my answer you can do this for yourself as well Commented Dec 20, 2015 at 19:19
• Not nearly enough information to answer. Depends first on whether your playing limit of no limit, the size of the pot, the size of your and your opponent's stacks, your position, and so on. Folding would be right if (a) the pot is very small, and (b) you won't be paid off when you make it because of small stacks or your knowledge of your opponent. Commented Dec 20, 2015 at 19:43
• What does "50 chips entrance" mean? The main questions here are what is the size of the pot before the turn card is dealt, and what is the specific turn action before the action is on you? You also say your opponent raised, but that implies that someone else bet first. Are you and your opponent the only players in the pot? Commented Dec 20, 2015 at 20:21

In general to calculate your percentage of hitting you can do the following:

• Count your outs. In your case: 13 cards of your suit minus the 4 you already see make 9 cards in the deck which will make your flush.
• Calculate the amount of cards left. Since we can not know the cards of our opponents, we include them in our calculation. Hence there are 52 -2 (your cards) - 3(flop) = 47 cards left.
• The probability you will make your flush on the turn is therefore 9/47. The probability you will make the flush on the river is 9/46.
• Since the events are dependent, combining the probability goes as follows: For the second event, we should calculate the probability that event 2 happens AND event 1 did not. Therefore: 9/46 * (1-9/47) = 0.16. Combining this with the probability of event 1 gives: 9/47 + 0.16 = 0.349 and hence about 35%
• On the turn, your hitting chance (if the flush did not come on the turn) would be 9/46 = 0.19, or 19%

Your strategy on the flop should therefore be: call when the pot-odds are lower than 35% (you have to pay less than 35% of the pot to call).

However, this calculation is quit cumbersome in practice. Therefore, here is a quick rule of thumb to approximate your hitting chance:

• Multiply with 4 on the flop to get 36%
• On the turn, you multiply with 2 and add 2 to get 20%

Note that both values are one percentage point larger than the actual odds. Call this optimistic evaluation.

• I was taught this rule years ago as "the rule of 2 and 4". 2 cards to come? Multiply your outs by 4 and subtract a little. 1 card to come, multiply your outs by 2 and add a little. Commented Dec 23, 2015 at 22:43
• It is the odds of hitting not winning. Opponent could have higher flush or even a full house if the board pairs. Commented Dec 25, 2015 at 15:07
• @Frisbee True, phrasing could be better. I will edit the answer. But if you read your opponent to have a higher flush draw you should fold or bluff anyway. Commented Dec 25, 2015 at 22:54
• What about "Implied Odds"? The above discussion - while good - doesn't consider the risk and rewards of subsequent bets. Can anyone provide analysis that does? Commented Dec 27, 2015 at 14:55
• @jbbenni I think that would make this question too broad. Also, implied odds can not be approached mathematically since you can not know how much the pot will grow or give probabilities to certain pot size outcomes. What you could do is take the 'all-in' as given and use the effective stack before the flop times two as pot size, but only if you are certain of an all-in if you hit. Commented Dec 27, 2015 at 16:25

At the turn your opponent bet 10 into a pot of 62 so you were getting proper odds to call.

What is scary here is that your opponent was giving you odds to stay in the pot. They may have been on a bigger flush draw. If you have the bigger flush draw you have a chance of stacking them. If you were like 7, 8 and your opponent makes a big bet on the river you have to think about getting away. If you make a flush and the board pairs you may be beat. Still you should have called - in my opinion.

Another way to looks at combined odds is to formulate the null hypothesis. Not hit on turn and river you can multiply.
1 - ( (47-9)/(47) * (46-9)/46) ) = 34.9676%

OR in statistics gets kind of messy so one approach is to flop is to the null hyposis so it becomes an AND. With an AND you can multiply.

It comes out the same as the accepted answer
I actually thought accepted answer wrong until I tested it out

Using pot odds ratio versus % is different.

• Ratio
Odds once you opponent bet 10 into the pot the pot was up to 72
• %
With % you need to add in you bet so your % pot odds is 10(62+10+10) = 12.2%
You want pot % to be less than your card % so you were getting very good odds to call

Ratio to me is easier
Let's look at the ratio to make the flush on the turn alone
9 cards make the flush (13 - 2 (in hand) - 2 (on board))
38 cards don't make the flush (52 - 5 (exposed) - 9 (that make the flush))