Poker Probability Calculator

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Poker Probability Calculator

Calculate your equity and drawing odds instantly

Cards that improve your hand.
Flop to Turn (1 Card) Turn to River (1 Card) Flop to River (2 Cards)
Win Probability 0%
Pot Odds Needed 0:1

Understanding Poker Probability

In Texas Hold'em, knowing your "outs" is the foundation of mathematical poker strategy. An out is any card left in the deck that will likely improve your hand to a winning one. For example, if you hold two hearts and the flop has two hearts, there are 9 hearts remaining in the deck (13 total hearts – 2 in hand – 2 on board) that will give you a flush.

The Rule of 2 and 4

Professional players often use a shortcut called the "Rule of 2 and 4" to estimate equity:

  • On the Flop: Multiply your outs by 4 to see the probability of hitting your hand by the River.
  • On the Turn: Multiply your outs by 2 to see the probability of hitting your hand on the River.

This calculator provides the precise mathematical calculation, which is slightly more accurate than the Rule of 2 and 4, especially when you have a large number of outs.

Common Outs Reference

Hand Drawing To Outs
Flush Draw 9
Open-Ended Straight Draw 8
Inside Straight (Gutshot) 4
Two Overcards to Top Pair 6
function calculatePokerProbability() { var outs = parseInt(document.getElementById('outs').value); var street = document.getElementById('street').value; var resultBox = document.getElementById('poker-result-box'); var winProbDisplay = document.getElementById('win-prob'); var oddsDisplay = document.getElementById('card-odds'); if (isNaN(outs) || outs 47) outs = 47; var probability = 0; if (street === 'flop-to-turn') { // Probability of hitting on the Turn (1 card) // 47 cards remaining (52 – 2 in hand – 3 on flop) probability = (outs / 47) * 100; } else if (street === 'turn-to-river') { // Probability of hitting on the River (1 card) // 46 cards remaining (52 – 2 in hand – 4 on board) probability = (outs / 46) * 100; } else if (street === 'flop-to-river') { // Probability of hitting on EITHER the Turn or River // 1 – (Prob of missing both) var missTurn = (47 – outs) / 47; var missRiver = (46 – outs) / 46; probability = (1 – (missTurn * missRiver)) * 100; } // Calculate Odds (X to 1) var oddsValue = 0; if (probability > 0 && probability = 100) { oddsValue = 0; } else { oddsValue = 999; } // Display Results winProbDisplay.innerText = probability.toFixed(1) + '%'; oddsDisplay.innerText = oddsValue.toFixed(2) + ':1'; resultBox.style.display = 'block'; }

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