What Is an Open-Ended Straight Draw?

Open-ended straight draw: definition

An open-ended straight draw is four cards in numerical order that need one more card at either end to become a straight. A straight itself is five cards in numerical order with mixed suits, so the draw is one card short of that, but with two different ranks that can finish the job¹.

The word "open-ended" is the whole point. Your four cards sit at the end of a run, not in the middle of one, so the sequence is open on both sides. If you hold 5-6-7-8, a 4 goes on the bottom and a 9 goes on top. Either one makes the straight. That is what separates it from a draw that is missing a card from the middle, where only one rank can help you.

A straight beats three of a kind, two pair and one pair, and it loses to a flush, a full house, four of a kind, a straight flush and a royal flush¹. The highest straight flush, A-K-Q-J-10 in the same suit, is the best hand in most poker variants, so a plain straight sits well below the top of the ladder but comfortably above the hands you will usually be up against when you are drawing³.

You will meet the draw in any game where players share community cards, and it works the same way in Texas Hold'em and in the Omaha family, where each player gets four hole cards and must use exactly two of them². The math below is the same in both.

Example: holding 5-6-7

Take the simplest version. You hold 5-6 and the flop comes 7-8-K. Your best five cards are not there yet, but look at what you have: 5-6-7-8, four cards in a row. Any 4 gives you 4-5-6-7-8. Any 9 gives you 5-6-7-8-9. Both are straights, and both are live.

That is an open-ended straight draw. The king on the flop is irrelevant to the straight, but it matters for everything else: it is a card your opponent might have paired, and it changes how much you want to put in the pot while you are still drawing.

The same shape shows up in other games, which is a useful way to remember it. In Liêng, a Vietnamese card game, a straight is three consecutive cards such as 4-5-6, and the odds of being dealt one are 3.26%, or about 1 in 31⁴. In Tiến lên, a straight is three or more consecutive cards, and in the Northern style they must also be the same suit; the 2 cannot be part of a straight, and a run from 3 up to ace is called a dragon straight⁵. The underlying idea is identical: consecutive ranks, one gap to fill.

If you want the full picture of how straights rank against everything else, the poker hand rankings page lays it out from royal flush down to high card.

Outs: 8 ways to complete the hand

An out is any card left in the deck that turns your hand into the one you are chasing. For an open-ended straight draw, count them like this:

• Four cards of the rank below your run. Holding 5-6-7-8, that is the four remaining 4s.
• Four cards of the rank above your run. That is the four remaining 9s.

Eight outs in total². Two of those cards, the ones that also match a suit you hold, could give you a straight flush instead, but they still count as outs for the straight.

Eight is a healthy number. For comparison, a flush draw has nine outs and a gutshot straight draw has four². That gap between eight and four is the reason players treat an open-ended draw as a real hand and a gutshot as a much thinner one.

Those figures come from a standard draw chart used for Omaha and hold'em alike². Notice how close the open-ended straight draw (31.5%) sits to the flush draw (35%) despite having one fewer out. Both are strong draws. Notice too what happens when you combine them: an open-ended straight flush draw, where the same cards that complete your straight also complete a flush, has 15 outs and gets there 54% of the time by the river². That is a favorite, not a draw.

One more comparison worth keeping in your head: if you hold a pocket pair and flop a set, you have one out to quads, and that comes in 4.3% of the time by the river². Drawing thin is a real thing, and eight outs is not thin.

Chance of improving: about 32% by the river

With eight outs and two cards to come, an open-ended straight draw completes about 31.5% of the time by the river². Call it roughly one time in three.

That number assumes you see both the turn and the river. If you fold on the turn, or your opponent bets you off the hand, you never realize the full 31.5%. This is the single most common mistake players make with draw math: they quote the by-the-river figure while only paying for one card.

The 31.5% also assumes all eight outs are live. If some of your outs are in your opponents' hands, or if a card that completes your straight also completes a bigger straight for someone else, your real chance is lower. The chart gives you the clean mathematical figure; the table gives you the messy version.

For a sense of scale, a personal card pairing on the flop happens 32.43% of the time⁶. Your open-ended straight draw arriving by the river is almost exactly as likely as that. It is a frequent enough event that an open-ended draw on the flop is far from a long shot, and rare enough that it is not a made hand.

If you want the wider picture of how outs, pot odds and equity fit together, the poker odds and probabilities page goes through the whole framework.

Odds on the turn vs the flop

The two numbers you actually use at the table are different, and mixing them up is expensive.

On the flop, with two cards to come: about 32%. Eight outs, two chances².

On the turn, with one card to come: about 17%. Eight outs, one chance. That is eight cards out of the 47 you have not seen, which works out to roughly one in six.

The turn figure is the one that matters most often, because by the turn the betting is bigger and your decision is more expensive. If you are calling a large bet on the turn with an open-ended draw, you are roughly a 5-to-1 underdog to hit on the river, and the pot needs to be offering you something close to that to make the call worthwhile on the draw alone.

A quick way to sanity-check the flop number in your head: multiply your outs by four for the turn and river together, and by two for the next card alone. Eight outs times four is 32, which matches the 31.5% chart figure. Eight times two is 16, close to the 17% turn figure. The shortcut is not exact, but it is close enough to size up the spot at the table.

For comparison, a flush draw with nine outs is 35% by the river², and a gutshot with four outs is 16.5%². If you can remember those three numbers, 32, 35 and 16.5, you can size up almost any drawing situation you will meet.

Other names for the draw

You will hear the same hand called several things, and they all mean eight outs from a four-card run:

• Open-ended draw. The short form, used constantly in hand discussion.
• Outside straight draw. Common in older poker books and still used by plenty of players.
• Two-way straight draw. Emphasizes that it can be completed from either end.
• OESD. The abbreviation you will see in hand histories, forums and training material.

None of these describe a different hand. If someone says "I had an outside draw" or "I had the OESD," they mean four consecutive cards with both ends live.

It helps to keep the term separate from a few things that sound similar but are not the same. A "straight" in a lottery game like PICK-3 or PICK-4 means matching your numbers to the winning numbers in the exact order drawn, which is a completely different use of the word⁷. In football betting, a "draw" is a match result, not a poker hand⁸. Poker's straight is its own thing.

If you are new to the vocabulary more broadly, the poker glossary covers terms from 3-bet to straddle, including this one.