Free tools for prediction market traders. Convert odds, calculate expected value, and find arbitrage opportunities.
In prediction markets like Polymarket and Kalshi, each contract trades between $0.01 and $0.99. The price directly represents the market's implied probability. A contract trading at 65¢ means the market collectively estimates a 65% chance the event will happen.
If the event happens, the contract pays $1.00. If it doesn't, it pays $0. Your profit is the difference between your buy price and $1.00 (if correct) or your loss is your buy price (if wrong).
Example: Buy at 45¢, event happens → you receive $1.00, profit = 55¢ per share (122% return). Event doesn't happen → you lose 45¢ per share.