Calculators
Free tools for prediction market traders.
Market Fees
Compare trading fees across Kalshi, Polymarket, PredictIt, and ProphetX.
Vig & No-Vig
Calculate the vig (juice) and find fair no-vig probabilities.
Expected Value
Determine if a bet has positive expected value (+EV).
Odds Converter
Convert between American, decimal, and implied probability.
Parlay
Calculate parlay odds, payouts, and ROI for multi-leg bets.