Poker Odds Calculator

Enter your outs and how many cards are left to come to get your chance of completing the draw (Rule of 4 and 2, plus the exact hypergeometric odds), then compare it to the pot odds you're being offered.

Quick Facts

Rule of 4 and 2
Outs × 4 (two cards to come) or outs × 2 (one card to come)
A fast mental estimate poker players use at the table.
Common out counts
Flush draw: 9 outs. Open-ended straight draw: 8 outs. Gutshot: 4 outs.
Counted from the 52-card deck minus your hole cards and the board.

Your Results

Calculated
Est. win chance (Rule of 4/2)
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Quick mental-math estimate
Exact win chance
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Hypergeometric probability
Odds against hitting
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Expressed as X : 1
Required equity (pot odds)
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Call ÷ (pot + call)

Ready

Enter your outs, cards to come, pot size, and bet to call, then press Calculate.

About the Poker Odds Calculator

This calculator turns your outs — the unseen cards that complete your draw — into a win probability, using the same math good players estimate at the table. It gives you both a fast mental-math approximation (the Rule of 4 and 2) and the exact hypergeometric probability, then compares that win chance to the pot odds you're being offered so you can judge whether a call is profitable in the long run.

The Rule of 4 and 2

Count your outs, then apply a quick multiplier depending on how many community cards are still to come:

  • Two cards to come (you're deciding on the flop, before the turn and river are dealt): multiply outs by 4 to estimate your percent chance of hitting by the river.
  • One card to come (you're deciding on the turn, only the river is left): multiply outs by 2.

Example: a flush draw (9 outs) on the flop is roughly 9 × 4 = 36% to complete by the river. The same draw on the turn, with only the river left, is roughly 9 × 2 = 18%.

The exact probability

The Rule of 4 and 2 is a close approximation, not the exact figure — it slightly overstates your odds as the out count grows. The exact probability comes from the hypergeometric distribution over the unseen cards in the deck:

  • One card to come: P = outs ÷ unseen cards.
  • Two cards to come: P = 1 − [(unseen − outs) × (unseen − outs − 1)] ÷ [unseen × (unseen − 1)] — one minus the probability that both remaining cards miss.

"Unseen cards" assumes only your two hole cards and the board are known (opponents' hole cards are treated as unseen): 47 unseen cards after the flop, 46 after the turn, out of the 52-card deck.

Comparing to pot odds

Pot odds tell you the minimum win probability (required equity) you need for a call to break even: required equity = bet to call ÷ (pot before your call + bet to call), as a percentage. If your win probability is higher than the required equity, calling is +EV (profitable on average over many repetitions of the same spot); if it's lower, calling loses money on average even though you might win this particular hand.

Frequently Asked Questions

What is an out in poker?
An out is any unseen card that improves your hand to (most likely) the best hand. For example, if you hold a four-card flush after the flop, there are 9 remaining cards of that suit in the deck, so you have 9 outs. Count outs by identifying every card that completes your draw, and be careful not to double-count cards that also help an opponent more than you.
What is the Rule of 4 and 2?
A fast mental shortcut for estimating your chance to hit a draw. With two cards still to come (on the flop), multiply outs by 4 for your approximate percent chance to hit by the river. With one card left (on the turn), multiply outs by 2. It's an approximation — the exact hypergeometric probability is slightly lower for large out counts.
What are pot odds and how do I use them?
Pot odds compare the cost of a call to the total pot: required equity equals the call amount divided by the pot plus the call amount, expressed as a percent. If your win probability is higher than that required equity percentage, calling is profitable in the long run; if it's lower, calling loses money on average.
How is the exact win probability calculated?
With one card to come, exact probability equals outs divided by unseen cards. With two cards to come, it's 1 minus the probability of missing both draws, calculated from the hypergeometric distribution over the unseen cards remaining in the deck (47 unseen after the flop, 46 after the turn).

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