How to use the poker probability calculator
- Count your outs: the specific remaining cards that will complete your winning hand.
- Select whether 1 or 2 cards are still to come (turn only, or turn and river).
- Enter the number of unseen cards. Use 47 after the flop or 46 on the turn in Texas Hold'em.
- Optionally enter the pot size and the bet you face to check if calling is mathematically correct.
- Read the probability, odds ratio, and pot odds verdict below.
How poker hand probability is calculated
The probability of hitting at least one out depends on how many cards are coming. For a single card, the formula is straightforward:
P = outs / unseen
For example, a flush draw has 9 outs with 47 unseen cards after the flop. The chance of hitting on the turn is 9 / 47 = 0.1915, or about 19.15%.
When two cards remain (turn and river), it is easier to calculate the chance of missing both and subtracting from 1:
P = 1 - ((unseen - outs) / unseen) * ((unseen - 1 - outs) / (unseen - 1))
Using the same flush draw: 1 - (38/47) * (37/46) = 1 - 0.6503 = 0.3497, giving roughly 34.97%. This poker probability calculator performs these steps instantly so you do not have to do the arithmetic at the table.
Common draws and their outs
Knowing how many outs each draw carries is essential for fast decisions. Here is a reference table for standard Texas Hold'em situations after the flop (47 unseen cards).
| Draw type | Outs | One card (%) | Two cards (%) |
|---|---|---|---|
| Gutshot straight | 4 | 8.51 | 16.47 |
| Two overcards (pair) | 6 | 12.77 | 24.14 |
| Open-ended straight | 8 | 17.02 | 31.45 |
| Flush draw | 9 | 19.15 | 34.97 |
| Straight + flush combo | 15 | 31.91 | 54.12 |
These figures assume none of your outs are dead. If an opponent holds one of your suit cards, reduce your outs accordingly.
Comparing hand odds to pot odds
Probability alone does not tell you whether to call. You need to compare your hand odds to the pot odds offered by the current bet. Pot odds are calculated as:
Pot odds = bet to call / (current pot + bet to call + bet to call)
If the pot is 100 chips and your opponent bets 50, the total pot becomes 150. You must call 50, so your pot odds are 50 / 200 = 25%. Your hand probability must exceed 25% for the call to be profitable in the long run.
A flush draw with two cards to come hits about 35% of the time, which beats the 25% threshold, making the call correct. A gutshot straight draw at roughly 16.5% would not justify the same call. This poker probability calculator handles that comparison automatically when you fill in the pot and bet fields.
The rule of two and four
At the table, players often use a shortcut called the rule of two and four instead of a full poker probability calculator. Multiply your outs by 2 for one card to come, or by 4 for two cards to come, to get an approximate percentage.
For a 9-out flush draw: 9 * 4 = 36% (actual is 34.97%), and 9 * 2 = 18% (actual is 19.15%). The approximation is close enough for quick decisions but loses accuracy with high out counts. With 15 outs, the rule gives 15 * 4 = 60% while the true value is 54.12%, an error large enough to change a decision.
Use the shortcut for speed during live play, but rely on exact calculations when reviewing hands or studying off the table.
Adjusting for blockers and dead outs
The default assumption of 47 unseen cards works for heads-up play right after the flop. In multi-way pots, other players hold cards that may include your outs. These are called dead outs or blockers.
If you have a flush draw and suspect an opponent holds two cards of your suit, your effective outs drop from 9 to 7. Always adjust the outs field in this tool to reflect what you know about opponents' ranges. Similarly, if you are on the turn rather than the flop, change the unseen cards to 46.
For deeper statistical analysis of entire hand distributions, you might also explore a general statistics calculator to model variance across sessions.
Worked examples
Each result below was produced by the same code the tool runs, so you can check your own numbers against them.
| Example | Input | Result |
|---|---|---|
| Flush draw on the flop | Number of outs: 9; Cards to come: 2; Unseen cards: 47; Current pot size: 100; Bet to call: 50 | Probability (two cards): 34.97%; Odds against: 1.86 to 1; Outs: 9; Unseen cards: 47; Pot odds: 25.00%; Decision: Call is profitable |
| Open-ended straight draw on the turn | Number of outs: 8; Cards to come: 1; Unseen cards: 46; Current pot size: 200; Bet to call: 50 | Probability (next card): 17.39%; Odds against: 4.75 to 1; Outs: 8; Unseen cards: 46; Pot odds: 16.67%; Decision: Call is profitable |
| Gutshot straight draw, one card to come | Number of outs: 4; Cards to come: 1; Unseen cards: 46 | Probability (next card): 8.70%; Odds against: 10.50 to 1; Outs: 4; Unseen cards: 46 |
| Set mining with a pocket pair on the flop | Number of outs: 2; Cards to come: 2; Unseen cards: 47; Current pot size: 60; Bet to call: 10 | Probability (two cards): 8.42%; Odds against: 10.88 to 1; Outs: 2; Unseen cards: 47; Pot odds: 12.50%; Decision: Call is not profitable |
FAQ
What are outs in poker?
Outs are the specific cards remaining in the deck that will improve your hand to a likely winner. A flush draw typically has 9 outs because there are 13 cards of each suit, you hold 2, and 2 are on the board.
Why are there 47 unseen cards after the flop?
A standard deck has 52 cards. You hold 2 hole cards and the flop reveals 3 community cards, leaving 52 minus 5, which equals 47 cards you cannot see.
How accurate is the rule of two and four?
It is a rough estimate. It works well for draws with fewer than 10 outs but overestimates significantly for combo draws with 12 or more outs. Use this poker probability calculator for exact numbers.
Does this tool account for multiple opponents?
The math assumes all unseen cards are equally likely to come. In multi-way pots, some of your outs may be in other players' hands. Reduce your outs manually to account for known or suspected blockers.
What if my pot odds exactly equal my hand probability?
That is a break-even situation. Over many identical spots, calling neither wins nor loses money. Most players fold here unless implied odds (future bets you expect to win) tip the balance.
Can I use this for Omaha or other variants?
Yes, but you must adjust the unseen cards count. In Omaha you hold 4 hole cards, so after the flop there are 52 minus 4 minus 3, which equals 45 unseen cards. The outs logic remains the same.