Betting Odds Converter

Convert betting odds between fractional, decimal and American formats — and calculate implied probability and potential payout.

Odds format

Numerator

Denominator

Stake (£)

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Fill in the details to get your result.

How This Works

Fractional odds (UK): numerator/denominator — profit/stake. Decimal (European): total return per £1 staked (includes stake). American: +500 means profit £500 per £100 stake; −200 means stake £200 to profit £100. Implied probability = 1/decimal odds × 100. All formats carry the same information — just presented differently.

Overround (or vig/juice) is the margin built into betting odds. If you add the implied probabilities of all outcomes in an event, they sum to more than 100% — typically 105–115% for most sports. The excess is the bookmaker's theoretical profit margin. For example, a coin flip should be 50%/50% but a bookmaker might offer 10/11 (52.4%) each side, creating 104.8% total — a 4.8% margin.