Advanced options
Implied probability is what the odds say the chance of winning is, before the bookmaker margin. Enter evens as 1/1, 2.0, +100 or 50 percent.
What The Odds Converter Works Out
- Fractional odds: the traditional UK format. 5/2 means you win GBP 5 for every GBP 2 staked, plus your stake back. The converter finds the closest simple fraction (denominator up to 100) for any decimal price.
- Decimal odds: used by exchanges and most of the world. The figure is your total return per GBP 1 staked, stake included, so 5/2 is 3.5 and evens is 2.0. To convert a fraction, divide the top by the bottom and add 1.
- American odds: a positive figure (+250) is the profit on a 100 stake; a negative figure (-150) is the stake needed to win 100. Prices shorter than evens are negative, longer than evens positive.
- Implied probability: 100 divided by the decimal odds. 5/2 implies a 28.6% chance. Because bookmakers build in a margin, the implied probabilities of every outcome in a market add up to more than 100%, so each one overstates the real chance slightly.
- Return on a GBP 10 stake: 10 multiplied by the decimal odds, with the stake included in the figure.
- Your stake (advanced): replaces the fixed GBP 10 so the profit and return cards use your actual bet size.
- Bookmaker overround (advanced): enter the market's total book (typically 2% to 8% on football and tennis match odds, 15% to 30% on racecards and specials) and the converter lengthens the price proportionally to show the fair odds and the true chance once the margin is stripped out.
- Price boost (advanced): bookmaker boosts add a percentage to the winnings part of the odds, not the stake. A 25% boost turns 2/1 into 5/2.
- Each way place odds (advanced): the place part of an each way bet pays at 1/4 or 1/5 of the win odds, so 5/2 becomes 1/2 at 1/5 terms. Useful for checking whether a placed bet covers the combined stake.
- Expected value per pound (advanced): your estimated chance multiplied by the decimal odds, minus 1. Positive means the price is bigger than your assessment says it should be. Without your own estimate it uses the fair chance, which gives roughly zero.
- Please gamble responsibly: free confidential support is available from GamCare on 0808 8020 133 or at gamcare.org.uk.