Convert American, Decimal, and Fractional odds instantly and calculate potential payouts.
American Odds (-110)
Decimal Odds (1.91)
Fractional Odds (10/11)
Total Payout:
Net Profit:
Implied Probability:
American Odds:
Decimal Odds:
Fractional Odds:
How to Use the Gambling Odds Calculator
Understanding betting odds is crucial for any gambler looking to manage their bankroll effectively. This calculator simplifies the process by converting different odds formats and calculating exactly how much profit you can expect from a winning bet.
The Three Main Odds Formats
American Odds (+/-): Commonly used in the US. Positive numbers show the profit on a $100 stake, while negative numbers show how much you must bet to win $100.
Decimal Odds: Popular in Europe and Australia. This represents the total return (stake + profit) for every $1 wagered.
Fractional Odds: Traditional in the UK. This represents the profit relative to the stake (e.g., 5/1 means you win $5 for every $1 bet).
Calculation Examples
If you place a $50 bet on a team with +200 American Odds:
Decimal Conversion: 3.00
Implied Probability: 33.33%
Net Profit: $100
Total Payout: $150
What is Implied Probability?
Implied probability is the likelihood of an outcome occurring as suggested by the odds. It is a critical metric for "value betting." If you believe the actual chance of an event happening is higher than the implied probability, you have found a value bet. The formula for decimal odds is (1 / decimal odds) * 100.
Betting Math Formulas
To calculate these values manually, use the following formulas:
American to Decimal (Positive): (Odds / 100) + 1
American to Decimal (Negative): (100 / |Odds|) + 1
Decimal to Fractional: (Decimal – 1) expressed as a simplified fraction.
Total Payout: Stake × Decimal Odds
function calculateGamblingOdds() {
var stake = parseFloat(document.getElementById('stakeAmount').value);
var format = document.getElementById('oddsFormat').value;
var rawOdds = document.getElementById('oddsInput').value;
if (isNaN(stake) || stake 0) {
decimalOdds = (am / 100) + 1;
} else {
decimalOdds = (100 / Math.abs(am)) + 1;
}
} else if (format === "decimal") {
decimalOdds = parseFloat(rawOdds);
} else if (format === "fractional") {
if (rawOdds.indexOf('/') !== -1) {
var parts = rawOdds.split('/');
var num = parseFloat(parts[0]);
var den = parseFloat(parts[1]);
decimalOdds = (num / den) + 1;
} else {
decimalOdds = parseFloat(rawOdds) + 1;
}
}
} catch (e) {
alert("Invalid odds format.");
return;
}
if (isNaN(decimalOdds) || decimalOdds = 2.0) {
americanConverted = "+" + Math.round((decimalOdds – 1) * 100);
} else {
americanConverted = Math.round(-100 / (decimalOdds – 1));
}
var fractionalConverted = decimalToFraction(decimalOdds – 1);
// Display
document.getElementById('resPayout').innerHTML = "$" + totalPayout.toFixed(2);
document.getElementById('resProfit').innerHTML = "$" + netProfit.toFixed(2);
document.getElementById('resProbability').innerHTML = impliedProb.toFixed(2) + "%";
document.getElementById('resAmerican').innerHTML = americanConverted;
document.getElementById('resDecimal').innerHTML = decimalOdds.toFixed(3);
document.getElementById('resFractional').innerHTML = fractionalConverted;
document.getElementById('resultsArea').style.display = "block";
}
function decimalToFraction(decimal) {
if (decimal === 0) return "0/1";
var gcd = function(a, b) {
return b ? gcd(b, a % b) : a;
};
var len = decimal.toString().length – 2;
var denominator = Math.pow(10, len);
var numerator = Math.round(decimal * denominator);
var divisor = gcd(numerator, denominator);
numerator /= divisor;
denominator /= divisor;
// Simplification for common betting odds
if (denominator > 1000) {
return (decimal.toFixed(2)) + "/1";
}
return Math.floor(numerator) + "/" + Math.floor(denominator);
}