Exact formula
one card: P = outs / unseen
two cards: P = 1 − (unseen − outs)/unseen × (unseen − outs − 1)/(unseen − 1)
Outs table (Texas Hold’em, 47 unseen on the flop)
| Outs | Typical draw | Flop → turn | Turn → river | Flop → river | Odds against (to river) | Rule of 4 |
|---|---|---|---|---|---|---|
| 2 | Pocket pair to a set | 4.3% | 4.3% | 8.4% | 10.9 : 1 | 8% |
| 3 | One overcard | 6.4% | 6.5% | 12.5% | 7.0 : 1 | 12% |
| 4 | Gutshot, two pair to full house | 8.5% | 8.7% | 16.5% | 5.1 : 1 | 16% |
| 5 | Pair + gutshot | 10.6% | 10.9% | 20.4% | 3.9 : 1 | 20% |
| 6 | Two overcards | 12.8% | 13.0% | 24.1% | 3.1 : 1 | 24% |
| 8 | Open-ended straight draw | 17.0% | 17.4% | 31.5% | 2.2 : 1 | 32% |
| 9 | Flush draw | 19.1% | 19.6% | 35.0% | 1.9 : 1 | 36% |
| 11 | Flush draw + overcard | 23.4% | 23.9% | 41.7% | 1.4 : 1 | 44% |
| 12 | Flush draw + gutshot | 25.5% | 26.1% | 45.0% | 1.2 : 1 | 48% |
| 15 | Flush draw + open-ender | 31.9% | 32.6% | 54.1% | 0.85 : 1 | 60% |
| 17 | Flush draw + open-ender + overcard | 36.2% | 37.0% | 59.8% | 0.67 : 1 | 68% |
| 20 | Flush draw + open-ender + pair | 42.6% | 43.5% | 67.5% | 0.48 : 1 | 80% |
For Short Deck set the unseen cards to 31 on the flop and 30 on the turn; for Omaha use 45 and 44.
Turning outs into a decision
Knowing you are 35% to hit is only half the job. Compare it with the required equity from pot odds: 35% beats the 33% you need to call a pot-sized bet, but not the 37.5% needed for a 1.5× pot bet. The implied odds calculator covers what to do when the price is not quite there.
Frequently asked questions
What is an out in poker?
A card that improves your hand to one that is likely to win. A flush draw has 9 outs (13 cards of the suit minus the 4 you see), an open-ended straight draw has 8, a gutshot has 4.
How does the rule of 2 and 4 work?
Multiply your outs by 2 for the chance to hit on the next card, or by 4 for the chance to hit by the river when you see both the turn and the river. It is within 1–2 points for up to 12 outs, then overshoots.
Why 47 unseen cards?
On the flop you have seen your 2 cards and 3 board cards: 52 − 5 = 47 unknown. On the turn it is 46. The opponent’s cards are unknown, so they count as unseen even though they are not in the deck.
Should I discount outs?
Yes, when a card that completes your hand could also give the opponent a better one. A straight draw on a two-tone board might have 6 clean outs instead of 8. Enter the discounted number.