Do you have the odds to call with a combo draw?

A combo draw (flush plus open-ended straight) has 15 outs: 31.9% on the turn, 32.6% on the river, and 54.1% by the river when both cards are guaranteed.

15 Outs

31.9% Hit on the next card (flop)

32.6% Hit on the river (turn)

54.1% By the river, both cards guaranteed

Table shortcut, outs × 2 for each card you see: 15 × 2 = 30% for a one-card call, and 15 × 4 = 60% when this flop call guarantees both cards. The exact numbers are 31.9% for one card and 54.1% for two. With this many outs the estimate is off by 2.6 points for one card and 5.9 for two, so trust the exact figures.

One-card direct odds assume you fold after a miss and pay no further bets. Use by-the-river odds when this call guarantees both cards, such as an all-in or a guaranteed free river.

When a flush draw and an open-ended straight draw arrive together you have 15 outs. From the flop one of them comes on the turn 31.9% of the time, which on direct odds alone pays for a bet up to about 88% of the pot. All-in on the flop you hit by the river 54.1% of the time, a favorite over most one-pair hands, which is why a combo draw is happy to get the money in and often raises as a semi-bluff. A set still has you beat, and so does an overpair that holds one of your straight cards. On the turn you hit 32.6% of the time, enough to call a bet just under pot.

On one-card direct odds, 15 outs can call a bet up to about 88% of the pot on the flop and up to about 94% of the pot on the turn on direct odds alone. When a flop call guarantees both cards, including all-in or a free river, both cards count, and then 15 outs can call a bet of any size. Anything bigger has to be paid back by what you win when you hit.

Quick tip: All-in on the flop, a 15-out combo draw is a favorite over one pair. Raise or get it in, do not fold.