How to Convert Prediction Market Prices to Betting Odds

Prediction markets like Polymarket, Kalshi, and PredictIt use a simple pricing system where the price directly represents the implied probability of an event occurring. A price of 65 means the market believes there's a 65% chance the event will happen. This calculator helps you convert these prediction market prices to traditional betting odds formats. Unlike traditional sportsbooks like FanDuel, DraftKings, and BetMGM, prediction markets have minimal fees built into their prices. Traditional sportsbooks add "vig" or "juice" to their odds, typically 4-10%, which reduces your expected returns. Prediction markets, on the other hand, usually charge small trading fees (0.5-2%), making them more efficient for bettors who understand probability. To use this calculator, simply enter a prediction market price (0-100) in the top field, and the calculator will instantly convert it to American odds, decimal odds, and fractional odds. You can also enter odds in any of the output fields to reverse-calculate the prediction market price. For example, if you see a prediction market price of 65 for an event, this converts to approximately -186 American odds, 1.54 decimal odds, and 13/20 fractional odds. This means you'd need to bet $186 to win $100 (plus your stake back) at a traditional sportsbook offering equivalent odds. Understanding these conversions is crucial for comparing value across different betting platforms. If a prediction market offers an event at 65 (implied 65% probability) but a sportsbook offers -150 American odds (implied 60% probability with vig removed), you can identify which platform offers better value for your bet.