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MyPokerOdds

What are the odds of hitting a flush draw?

With a flush draw on the flop you complete the flush 34.97% of the time by the river, and 19.15% on the turn alone.

Probability
34.97%
about 1 time in 2.9
on the next card
19.15%
Exact. Hypergeometric probability over the 47 unseen cards.

With four cards of one suit, nine of the thirteen remain unseen. Nine outs from 47 unseen cards is 19.15% on the turn; with two cards to come the chance of hitting at least once is 34.97% — a little over one time in three.

The Rule of 4 says 36%; the Rule of 2 says 18%. Both are within about a point. Remember that not every flush is the best hand: a paired board can give an opponent a full house, and a lower flush loses to a higher one.

  1. Outs to a flush9
  2. Unseen cards on the flop4752 − 2 − 3
  3. Ways to miss twice703C(38, 2) = 703
  4. Total two-card run-outs1,081C(47, 2) = 1081
  5. Probability of hitting by the river34.97%1 − 703 / 1081
  6. Rule of 4 estimate36.00%9 × 4%
  7. On the turn alone19.15%9 / 47
  8. Rule of 2 (turn)18.00%9 × 2%

Quick check

A flush draw on the flop — how often does it get there by the river?

Show answer

34.97%, about 35%.

Try it

Change any card; the numbers recompute from the same engine that produced the answer above.

Your hand
Board
Hand now
Ace High
Outs
15
of 47 unseen
By the turn
31.9%
15 / 47
By the river
54.1%
two cards to come

The 15 highlighted cards are your outs.

What you’re drawing to

  • Flush draw9 outs
  • Backdoor straight draw0.93%

    10 of the 1081 turn-and-river combinations make a straight.

  • Two overcards6 outs

    Pairing an overcard makes top pair, which is not always the best hand.

Shortcut vs. exact

Cards to comeRule of 2/4ExactGap
Turn only30%31.91%1.91 pts
Turn and river60%54.12%+5.88 pts

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