American (+300, -150)
Decimal (1.50, 2.25)
Fractional (1/2, 5/4)
Potential Payout:
$0.00
What is an NFL Parlay and How Does This Calculator Work?
An NFL parlay is a type of sports bet that combines multiple individual bets (called "legs" or "selections") into a single wager.
For the parlay to win, all individual legs must win. If even one leg loses, the entire parlay bet is a loss.
The appeal of parlays lies in their potential for significantly higher payouts compared to single bets, as the odds multiply with each additional leg.
Key Concepts:
Stake: This is the amount of money you are wagering on the parlay.
Legs (Selections): Each individual bet within the parlay. For example, betting on the Packers to win, the total points to be over 45.5, and Aaron Rodgers to throw for over 2.5 touchdowns would be a 3-leg parlay.
Odds: These represent the potential payout for each individual leg and, crucially, how they combine for the parlay. This calculator supports three common odds formats:
American Odds: These are shown with a plus (+) or minus (-) sign. Positive numbers (e.g., +150) indicate the profit on a $100 bet. Negative numbers (e.g., -110) indicate the amount you must bet to win $100.
Decimal Odds: These are straightforward. The number represents the total return (stake + profit) for every $1 wagered. For example, odds of 2.50 mean a $10 bet returns $25.
Fractional Odds: Shown as a fraction (e.g., 3/4). The top number (numerator) is the profit, and the bottom number (denominator) is the stake. So, 3/4 means you win $3 for every $4 you bet.
Potential Payout: This is the total amount you would receive if your parlay wins, including your original stake.
How the Calculator Works:
This calculator simplifies the process of determining your potential winnings. You input:
Your Stake (the amount you're betting).
The Number of Legs in your parlay.
The Odds Format you are using.
The specific Odds for each leg in your chosen format. For simplicity, this calculator handles up to two legs initially, and the total parlay odds are calculated based on the multiplication of individual leg odds. For parlays with more than two legs, the principle remains the same: multiply the odds of each leg together.
The calculator then converts all odds to a common format (decimal is often used internally for calculation) and multiplies them together. Finally, it multiplies the combined odds by your stake to show your potential total return.
Example Calculation (American Odds):
Let's say you place a $100 stake on a 2-leg parlay with the following American odds:
Your potential payout would be approximately $477.25.
This calculator will perform these steps automatically based on your inputs, providing a quick and accurate estimate of your parlay winnings. Remember, parlays are high-risk, high-reward bets. Always gamble responsibly.
function convertAmericanToDecimal(americanOdds) {
var odds = parseFloat(americanOdds);
if (isNaN(odds)) return 1;
if (odds >= 0) {
return (odds / 100) + 1;
} else {
return (100 / Math.abs(odds)) + 1;
}
}
function convertFractionalToDecimal(numerator, denominator) {
var num = parseFloat(numerator);
var den = parseFloat(denominator);
if (isNaN(num) || isNaN(den) || den === 0) return 1;
return (num / den) + 1;
}
function calculateParlay() {
var stake = parseFloat(document.getElementById("stake").value);
var legs = parseInt(document.getElementById("legs").value);
var oddsFormat = document.getElementById("oddsFormat").value;
if (isNaN(stake) || stake <= 0) {
alert("Please enter a valid stake amount.");
return;
}
if (isNaN(legs) || legs < 1) {
alert("Please enter a valid number of legs (at least 1).");
return;
}
var totalDecimalOdds = 1;
var validLegs = 0;
if (oddsFormat === "american") {
for (var i = 1; i 2), assume it's valid for calculation logic
// but we should ideally prompt for more inputs or handle this better for > 2 legs.
// For this example, we'll stop at 2 legs for simplicity in the HTML structure.
if (i > 2) {
alert("This calculator currently supports up to 2 legs for American odds input.");
return;
}
}
}
} else if (oddsFormat === "decimal") {
for (var i = 1; i = 1.01) {
totalDecimalOdds *= decimalOdds;
validLegs++;
} else {
alert("Please enter valid decimal odds (>= 1.01) for all legs.");
return;
}
} else {
if (i > 2) {
alert("This calculator currently supports up to 2 legs for Decimal odds input.");
return;
}
}
}
} else if (oddsFormat === "fractional") {
for (var i = 1; i 0) {
totalDecimalOdds *= convertFractionalToDecimal(numerator, denominator);
validLegs++;
} else {
alert("Please enter valid fractional odds (denominator > 0) for all legs.");
return;
}
} else {
if (i > 2) {
alert("This calculator currently supports up to 2 legs for Fractional odds input.");
return;
}
}
}
}
// Ensure we processed the correct number of legs that have inputs
if (validLegs !== legs && legs > 2) {
alert("Please ensure you have provided inputs for all " + legs + " legs. This example calculator only shows inputs for 2 legs. For more legs, the odds multiplication logic continues.");
return;
}
if (validLegs === 0 && legs > 0) {
alert("No valid odds were entered.");
return;
}
var potentialPayout = stake * totalDecimalOdds;
document.getElementById("result-value").innerText = "$" + potentialPayout.toFixed(2);
}
function updateOddsInputs() {
var oddsFormat = document.getElementById("oddsFormat").value;
document.getElementById("americanOddsInputs").style.display = (oddsFormat === "american") ? "block" : "none";
document.getElementById("decimalOddsInputs").style.display = (oddsFormat === "decimal") ? "block" : "none";
document.getElementById("fractionalOddsInputs").style.display = (oddsFormat === "fractional") ? "block" : "none";
// Basic handling for showing up to 2 legs; more robust UI would dynamically add inputs.
var numLegs = parseInt(document.getElementById("legs").value);
if (numLegs 2) {
alert("This basic example calculator only displays input fields for up to 2 legs. The underlying calculation logic assumes you would continue multiplying odds for more legs.");
// Adjust numLegs for display purposes if it exceeds the predefined inputs
numLegs = 2;
}
// Re-apply display based on format for the visible legs
var legInputsToShow = [
"americanOdds1", "americanOdds2",
"decimalOdds1", "decimalOdds2",
"fractionalOdds1Numerator", "fractionalOdds1Denominator",
"fractionalOdds2Numerator", "fractionalOdds2Denominator"
];
legInputsToShow.forEach(function(id) {
var element = document.getElementById(id);
if (element) {
var isAmerican = oddsFormat === "american";
var isDecimal = oddsFormat === "decimal";
var isFractional = oddsFormat === "fractional";
var legNumber = parseInt(id.match(/\d+$/)[0]); // Extracts the leg number from the ID
if (legNumber <= numLegs) {
element.closest('.input-group').style.display = 'block';
} else {
element.closest('.input-group').style.display = 'none';
}
}
});
}
document.getElementById("oddsFormat").addEventListener("change", updateOddsInputs);
document.getElementById("legs").addEventListener("change", updateOddsInputs);
updateOddsInputs(); // Initialize on page load