Sports Betting Odds Calculator

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Sports Betting Odds Calculator

American (+/-) Decimal (e.g., 2.50) Fractional (e.g., 5/2)

Results

Total Payout:

Total Profit:

Implied Probability:

Equivalent Odds:

  • American:
  • Decimal:
  • Fractional:
function calculateOdds() { var stake = parseFloat(document.getElementById('betStake').value); var format = document.getElementById('oddsFormat').value; var oddsInput = document.getElementById('oddsValue').value.trim(); var decimalOdds = 0; if (isNaN(stake) || stake 0) { decimalOdds = (am / 100) + 1; } else if (am < 0) { decimalOdds = (100 / Math.abs(am)) + 1; } else { throw "Invalid American Odds"; } } else if (format === 'decimal') { decimalOdds = parseFloat(oddsInput); if (decimalOdds <= 1) throw "Decimal odds must be greater than 1"; } else if (format === 'fractional') { if (oddsInput.indexOf('/') !== -1) { var parts = oddsInput.split('/'); var num = parseFloat(parts[0]); var den = parseFloat(parts[1]); decimalOdds = (num / den) + 1; } else { decimalOdds = parseFloat(oddsInput) + 1; } } if (isNaN(decimalOdds) || decimalOdds = 2) { convAm = "+" + Math.round((decimalOdds – 1) * 100); } else { convAm = Math.round(-100 / (decimalOdds – 1)); } // Fractional conversion (simplification) function getFraction(dec) { var val = dec – 1; var bestNum = 1; var bestDen = 1; var minErr = Math.abs(val – 1); for (var d = 1; d <= 100; d++) { var n = Math.round(val * d); var err = Math.abs(val – n / d); if (err < minErr) { minErr = err; bestNum = n; bestDen = d; } } return bestNum + "/" + bestDen; } var convFrac = getFraction(decimalOdds); document.getElementById('resPayout').innerText = "$" + payout.toFixed(2); document.getElementById('resProfit').innerText = "$" + profit.toFixed(2); document.getElementById('resProb').innerText = impliedProb.toFixed(2) + "%"; document.getElementById('convAmerican').innerText = convAm; document.getElementById('convDecimal').innerText = convDec; document.getElementById('convFractional').innerText = convFrac; document.getElementById('oddsResult').style.display = 'block'; } catch (e) { alert("Invalid odds format entered. Please check your input."); } }

Understanding Sports Betting Odds

Sports betting odds represent the probability of an event occurring and determine how much money you can win on a given bet. Whether you are betting on the Super Bowl, the Premier League, or a local horse race, understanding how to read and calculate these numbers is essential for long-term success.

Common Betting Odds Formats

Depending on where you live or which sportsbook you use, you will encounter three primary types of odds:

  • American Odds (+/-): Common in the United States. Positive numbers (+) indicate how much profit you make on a $100 bet. Negative numbers (-) indicate how much you need to bet to make a $100 profit.
  • Decimal Odds: Standard in Europe, Canada, and Australia. These represent the total return (stake + profit) for every $1 wagered. For example, odds of 2.00 mean you double your money.
  • Fractional Odds: Traditional in the UK and Ireland. Written as 5/1 (five-to-one), the first number is the potential profit and the second number is the stake.

How to Calculate Payouts and Profits

Calculating your potential return is straightforward once you have the decimal format. Here are the formulas used in this calculator:

Total Payout = Stake × Decimal Odds

Total Profit = Total Payout – Stake

Implied Probability = (1 / Decimal Odds) × 100

Real-World Example

Imagine you want to bet on a basketball game where the underdog has American odds of +150. You decide to stake $50.

  1. Convert to Decimal: (+150 / 100) + 1 = 2.50.
  2. Calculate Payout: $50 × 2.50 = $125.00.
  3. Calculate Profit: $125.00 – $50.00 = $75.00.
  4. Implied Probability: (1 / 2.50) = 40%.

In this scenario, if the underdog wins, you walk away with $125 total, consisting of your original $50 bet and $75 in profit.

Why Implied Probability Matters

Implied probability is the conversion of betting odds into a percentage. It represents the likelihood of an outcome according to the bookmaker. Professional bettors look for "value," which occurs when they believe the actual chance of a team winning is higher than the implied probability suggested by the odds.

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