Enter two cards, separated by a space. Suits: h, d, c, s. Ranks: 2-9, T, J, Q, K, A.
Enter up to three cards, separated by a space. Format: RankSuit.
Enter opponent's two cards if known.
Estimated Odds to Improve
–%
Understanding Omaha Poker Odds
Omaha poker is a popular variant where players are dealt four hole cards and must use exactly two of their hole cards in combination with exactly three community cards (the board) to make the best five-card hand. This calculator helps estimate your chances of improving your hand on the flop, turn, or river, given your hole cards, the visible board cards, and potentially your opponent's hole cards.
How the Calculator Works
This calculator estimates your odds of making a specific type of hand (e.g., a straight, a flush, a full house) or improving your current hand ranking. It does this by considering:
Your Hole Cards: The four cards dealt to you.
Community Cards (Board): The cards dealt face-up on the table.
Remaining Deck: The cards yet to be dealt (turn and river).
Opponent's Hole Cards (if known): These cards are removed from the deck, affecting the probabilities.
The calculator simulates the possible combinations of remaining cards to determine the probability of hitting outs (cards that improve your hand) versus being outdrawn.
Key Concepts in Omaha Odds Calculation:
1. Outs:
An 'out' is any card that will complete your hand and make it the winning hand. For example, if you have a flush draw (four cards of the same suit) and need one more card of that suit to complete your flush, there are typically 9 outs remaining in the deck (13 total cards of that suit – 4 you hold = 9).
2. Pot Odds:
Pot odds are the ratio of the current size of the pot to the cost of a contemplated call. While this calculator focuses on hand improvement odds, understanding pot odds is crucial for making profitable decisions in Omaha. You compare your calculated odds of improving to the pot odds to decide if calling a bet is mathematically worthwhile.
3. Rule of 4 and 2:
A common shortcut for estimating odds in poker is the 'rule of 4 and 2'.
If there are 2 cards left to come (e.g., you are on the flop and want to know your chances by the river), multiply your outs by 4 to get an approximate percentage chance of hitting your hand.
If there is 1 card left to come (e.g., you are on the turn), multiply your outs by 2 to get an approximate percentage chance.
This calculator provides more precise calculations but the rule of 4 and 2 is a useful quick estimation tool.
When to Use This Calculator:
Decision Making: To assess if you have sufficient equity (chance of winning) to continue in a hand, especially when facing bets.
Learning and Practice: To better understand hand probabilities and how draws develop in Omaha.
Hand Analysis: To review past hands and see what your odds were at different stages.
Remember, poker is a game of incomplete information. This calculator provides valuable probabilities, but reading opponents and understanding table dynamics are also critical components of successful Omaha play.
// — Card Representation —
// Ranks: 2, 3, 4, 5, 6, 7, 8, 9, T, J, Q, K, A
// Suits: h (hearts), d (diamonds), c (clubs), s (spades)
var ranks = ['2', '3', '4', '5', '6', '7', '8', '9', 'T', 'J', 'Q', 'K', 'A'];
var suits = ['h', 'd', 'c', 's'];
// — Helper Functions —
function parseCard(cardStr) {
if (cardStr.length 3) return null; // Invalid format
var rankStr = cardStr.slice(0, -1).toUpperCase();
var suitStr = cardStr.slice(-1).toLowerCase();
if (!ranks.includes(rankStr) || !suits.includes(suitStr)) return null; // Invalid rank or suit
return { rank: rankStr, suit: suitStr };
}
function cardsToString(card) {
return card.rank + card.suit;
}
function areCardsEqual(card1, card2) {
return card1.rank === card2.rank && card1.suit === card2.suit;
}
function isValidHand(hand) {
if (!Array.isArray(hand) || hand.length !== 2) return false;
for (var i = 0; i 3 || board.length < 1) return false;
for (var i = 0; i < board.length; i++) {
if (!board[i] || !board[i].rank || !board[i].suit) return false;
}
// Check for duplicate cards within the board
for (var i = 0; i < board.length; i++) {
for (var j = i + 1; j < board.length; j++) {
if (areCardsEqual(board[i], board[j])) return false;
}
}
return true;
}
function isValidOpponentHand(hand) {
return isValidHand(hand);
}
function isFlush(hand) {
if (hand.length < 5) return false;
var suit = hand[0].suit;
for (var i = 1; i < hand.length; i++) {
if (hand[i].suit !== suit) return false;
}
return true;
}
function getFlushSuit(hand) {
if (hand.length < 5) return null;
var suitCounts = {};
for (var i = 0; i = 5) return s;
}
return null;
}
function isStraight(hand) {
if (hand.length < 5) return false;
var uniqueRanks = [];
var rankValues = {'2': 2, '3': 3, '4': 4, '5': 5, '6': 6, '7': 7, '8': 8, '9': 9, 'T': 10, 'J': 11, 'Q': 12, 'K': 13, 'A': 14};
// Get unique ranks and sort them numerically
var seenRanks = new Set();
for (var i = 0; i < hand.length; i++) {
if (!seenRanks.has(hand[i].rank)) {
uniqueRanks.push(hand[i]);
seenRanks.add(hand[i].rank);
}
}
uniqueRanks.sort(function(a, b) {
return rankValues[a.rank] – rankValues[b.rank];
});
if (uniqueRanks.length < 5) return false;
// Check for standard straights
for (var i = 0; i <= uniqueRanks.length – 5; i++) {
var possibleStraight = true;
for (var j = 0; j < 4; j++) {
if (rankValues[uniqueRanks[i + j + 1].rank] !== rankValues[uniqueRanks[i + j].rank] + 1) {
possibleStraight = false;
break;
}
}
if (possibleStraight) return true;
}
// Check for A-5 straight (Ace low)
var hasAce = false;
var hasRank5 = false;
for (var i = 0; i < uniqueRanks.length; i++) {
if (uniqueRanks[i].rank === 'A') hasAce = true;
if (uniqueRanks[i].rank === '5') hasRank5 = true;
}
if (hasAce && hasRank5) {
var has2 = false, has3 = false, has4 = false;
for (var i = 0; i < uniqueRanks.length; i++) {
if (uniqueRanks[i].rank === '2') has2 = true;
if (uniqueRanks[i].rank === '3') has3 = true;
if (uniqueRanks[i].rank === '4') has4 = true;
}
if (has2 && has3 && has4) return true;
}
return false;
}
function getStraightHighCardRankValue(hand) {
if (hand.length < 5) return 0;
var uniqueRanks = [];
var rankValues = {'2': 2, '3': 3, '4': 4, '5': 5, '6': 6, '7': 7, '8': 8, '9': 9, 'T': 10, 'J': 11, 'Q': 12, 'K': 13, 'A': 14};
var seenRanks = new Set();
for (var i = 0; i < hand.length; i++) {
if (!seenRanks.has(hand[i].rank)) {
uniqueRanks.push(hand[i]);
seenRanks.add(hand[i].rank);
}
}
uniqueRanks.sort(function(a, b) {
return rankValues[a.rank] – rankValues[b.rank];
});
// Check for standard straights
for (var i = 0; i <= uniqueRanks.length – 5; i++) {
var possibleStraight = true;
for (var j = 0; j < 4; j++) {
if (rankValues[uniqueRanks[i + j + 1].rank] !== rankValues[uniqueRanks[i + j].rank] + 1) {
possibleStraight = false;
break;
}
}
if (possibleStraight) return rankValues[uniqueRanks[i + 4].rank];
}
// Check for A-5 straight (Ace low)
var hasAce = false;
var hasRank5 = false;
for (var i = 0; i < uniqueRanks.length; i++) {
if (uniqueRanks[i].rank === 'A') hasAce = true;
if (uniqueRanks[i].rank === '5') hasRank5 = true;
}
if (hasAce && hasRank5) {
var has2 = false, has3 = false, has4 = false;
for (var i = 0; i < uniqueRanks.length; i++) {
if (uniqueRanks[i].rank === '2') has2 = true;
if (uniqueRanks[i].rank === '3') has3 = true;
if (uniqueRanks[i].rank === '4') has4 = true;
}
if (has2 && has3 && has4) return rankValues['5']; // 5 is the high card for A-5 straight
}
return 0; // No straight found
}
function getHandRank(hand) {
// This is a simplified rank evaluation for demonstration.
// A full Omaha hand evaluator is complex due to 4 hole cards and 5 board cards.
// This will focus on simple draws and made hands for the purpose of odds calculation.
// Returns a numerical representation of hand strength:
// 0: High Card
// 1: Pair
// 2: Two Pair
// 3: Three of a Kind
// 4: Straight
// 5: Flush
// 6: Full House
// 7: Four of a Kind
// 8: Straight Flush
// 9: Royal Flush (subset of Straight Flush)
var ranksCount = {};
var suitsCount = {};
var rankValues = {'2': 2, '3': 3, '4': 4, '5': 5, '6': 6, '7': 7, '8': 8, '9': 9, 'T': 10, 'J': 11, 'Q': 12, 'K': 13, 'A': 14};
for (var i = 0; i = 5) {
hasFlush = true;
flushSuit = suit;
break;
}
}
var hasStraight = isStraight(hand);
var straightHighCardValue = 0;
if (hasStraight) {
straightHighCardValue = getStraightHighCardRankValue(hand);
}
// Check for Straight Flush / Royal Flush
if (hasFlush && hasStraight) {
// Need to check if the straight is *within* the flush suit
var flushCards = hand.filter(card => card.suit === flushSuit);
if (isStraight(flushCards)) {
var sfHighCardValue = getStraightHighCardRankValue(flushCards);
if (sfHighCardValue === rankValues['A']) return 9; // Royal Flush
return 8; // Straight Flush
}
}
if (numQuads === 1) return 7; // Four of a Kind
if (numTrips === 1 && numPairs >= 1) return 6; // Full House
if (hasFlush) return 5; // Flush
if (hasStraight) return 4; // Straight
if (numTrips === 1) return 3; // Three of a Kind
if (numPairs === 2) return 2; // Two Pair
if (hasPair) return 1; // Pair
return 0; // High Card
}
// — Main Calculation Logic —
function calculateOmahaOdds() {
var holeCardsStr = document.getElementById('holeCards').value.trim();
var boardCardsStr = document.getElementById('boardCards').value.trim();
var opponentHoleCardsStr = document.getElementById('opponentHoleCards').value.trim();
var resultDiv = document.getElementById('result-value');
var descriptionDiv = document.getElementById('result-description');
resultDiv.innerText = "Error";
descriptionDiv.innerText = "";
// 1. Parse Input Cards
var yourHoleCardsParsed = [];
var boardCardsParsed = [];
var opponentHoleCardsParsed = [];
var cardStrings = holeCardsStr.split(/\s+/);
for (var i = 0; i < cardStrings.length; i++) {
if (cardStrings[i]) {
var card = parseCard(cardStrings[i]);
if (card) yourHoleCardsParsed.push(card);
}
}
cardStrings = boardCardsStr.split(/\s+/);
for (var i = 0; i < cardStrings.length; i++) {
if (cardStrings[i]) {
var card = parseCard(cardStrings[i]);
if (card) boardCardsParsed.push(card);
}
}
cardStrings = opponentHoleCardsStr.split(/\s+/);
for (var i = 0; i < cardStrings.length; i++) {
if (cardStrings[i]) {
var card = parseCard(cardStrings[i]);
if (card) opponentHoleCardsParsed.push(card);
}
}
// 2. Validate Input
if (yourHoleCardsParsed.length !== 2) {
descriptionDiv.innerText = "Please enter exactly two of your hole cards.";
return;
}
if (boardCardsParsed.length 3) {
descriptionDiv.innerText = "Please enter between 1 and 3 community cards.";
return;
}
if (opponentHoleCardsParsed.length > 0 && opponentHoleCardsParsed.length !== 2) {
descriptionDiv.innerText = "If providing opponent's cards, please enter exactly two.";
return;
}
// Check for duplicate cards among your hole cards, board cards, and opponent's cards
var allKnownCards = […yourHoleCardsParsed, …boardCardsParsed, …opponentHoleCardsParsed];
var seenCardStrings = new Set();
for (var i = 0; i < allKnownCards.length; i++) {
var cardStr = cardsToString(allKnownCards[i]);
if (seenCardStrings.has(cardStr)) {
descriptionDiv.innerText = "Duplicate card detected: " + cardStr;
return;
}
seenCardStrings.add(cardStr);
}
// 3. Determine Current Hand Strength (Simplified)
// For odds calculation, we are most interested in the *potential* to improve.
// We need to know the best possible 5-card hand from your 4 hole cards + board cards.
var possibleHands = getAllCombinations(yourHoleCardsParsed, boardCardsParsed);
var bestCurrentHandRank = -1;
var bestCurrentHandCards = [];
for(var i=0; i bestCurrentHandRank) {
bestCurrentHandRank = currentHandRank;
bestCurrentHandCards = possibleHands[i];
}
}
// 4. Simulate Future Cards and Calculate Odds
var totalOuts = 0;
var totalPossibleFutureCards = 0;
var deck = createDeck(allKnownCards); // Create deck excluding known cards
var cardsToCome = 5 – boardCardsParsed.length; // Number of cards needed to complete the board (turn, river)
var improvementOccurred = false; // Flag to check if any improvement is possible
if (cardsToCome === 2) { // Calculating for Turn + River
totalPossibleFutureCards = deck.length * (deck.length – 1);
if (totalPossibleFutureCards === 0) {
resultDiv.innerText = "0.00%";
descriptionDiv.innerText = "No more cards can be dealt. Deck is exhausted.";
return;
}
for (var i = 0; i < deck.length; i++) {
for (var j = 0; j bestCurrentHandRank) {
totalOuts++;
}
}
}
} else if (cardsToCome === 1) { // Calculating for River only
totalPossibleFutureCards = deck.length;
if (totalPossibleFutureCards === 0) {
resultDiv.innerText = "0.00%";
descriptionDiv.innerText = "No more cards can be dealt. Deck is exhausted.";
return;
}
for (var i = 0; i bestCurrentHandRank) {
totalOuts++;
}
}
} else {
descriptionDiv.innerText = "Calculation is for completion of the board (Turn & River).";
return;
}
// 5. Display Result
var percentage = 0;
if (totalPossibleFutureCards > 0) {
percentage = (totalOuts / totalPossibleFutureCards) * 100;
}
resultDiv.innerText = percentage.toFixed(2) + "%";
var improvementDescription = "";
if (percentage === 0) {
improvementDescription = "You have no outs to improve your hand based on the known cards.";
} else {
improvementDescription = "Estimated odds of improving your hand by the river.";
if (cardsToCome === 1) improvementDescription = "Estimated odds of improving your hand on the river.";
}
descriptionDiv.innerText = improvementDescription;
}
// — Advanced Helper Functions for Omaha —
function createDeck(excludeCards) {
var deck = [];
for (var s of suits) {
for (var r of ranks) {
deck.push({ rank: r, suit: s });
}
}
// Remove excluded cards
var excludedCardStrings = new Set();
for (var i = 0; i !excludedCardStrings.has(cardsToString(card)));
}
function getAllCombinations(yourHole, board) {
// In Omaha, you must use EXACTLY 2 hole cards and EXACTLY 3 community cards.
// This function generates all possible 5-card hands using this rule.
var possibleHands = [];
var numCommunityCardsNeeded = 3;
// Generate combinations of 2 hole cards
var holeCombinations = getCombinations(yourHole, 2);
// Generate combinations of 3 board cards
var boardCombinations = getCombinations(board, numCommunityCardsNeeded);
for (var i = 0; i < holeCombinations.length; i++) {
for (var j = 0; j arr.length) return [];
var firstElement = arr[0];
var rest = arr.slice(1);
var combsWithFirst = getCombinations(rest, k – 1).map(function(comb) {
return [firstElement, …comb];
});
var combsWithoutFirst = getCombinations(rest, k);
return […combsWithFirst, …combsWithoutFirst];
}
// — Initial Setup —
document.addEventListener('DOMContentLoaded', function() {
// You could add default values or initial setup here if needed.
});