Open-ended straight draw: When you are on a straight draw, you have completed four out of five cards to a straight and you need the fifth card from either end to complete your straight. For example if you are holding Q10 of Diamonds and the flop is 9 of spades, J of hearts and 2 of clubs. You have an open-ended straight draw. You need an eight or a king to complete the straight.
Like most poker players, I get really excited when I flop an open-ended straight draw. I know that I have a good chance to hit a straight and potentially taking down a big pot. But, before I start celebrating...I need to know my odds of completing the straight.
How do I calculate my odds of hitting a straight and is it worth the investment? The first thing that I do is count the number of outs I have. I'm going to use the scenario I mentioned above. Since we need an eight or king to complete the straight, we have a total of 8 outs (4 eights and 4 kings). Each out gives us about 2% on the turn and 2% on the river (1 out of 47 on the turn and 1 out of 46 on the river for each out). Since we have eight outs, that gives us about 16% on the turn and 16% on the river. For a total of about 32%, basically 1 out of 3. In order for us to make a call we need 3 to 1 on our potential win to continue playing. If we are not going to get at least 3 to 1 on our money then we shouldn't chase the straight.
Chasing a straight and hitting the straight will help you win big pots, but it can also spell disasters. Some player tend to chase an open-ended straight draws even if there is a flush draw or a paired board out there as well and they don't have a flush draw. I have learned to fold open-ended straight draws when the board is paired or there is a flush draw on the board. More than often you hit your straight when someone else hits their flush or full-house and you end-up losing your entire chip stack because it's hard to lay down a straight.
Play Hard, Play Smart and Count your Outs