Free Trading Tools
Calculate probabilities, optimize bet sizes, and find arbitrage opportunities across prediction markets. All free, no signup required.
Probability Calculator
Convert contract prices to implied probabilities, calculate breakeven points with fees, and find expected value on any trade.
Open tool →Kelly Criterion Calculator
Calculate optimal bet sizing using the Kelly criterion. Find the mathematically ideal position size for any edge you identify.
Open tool →Arbitrage Scanner
Find cross-platform arbitrage opportunities between Kalshi and Polymarket. Calculate guaranteed profits after fees.
Open tool →Portfolio Calculator
Analyze your portfolio risk, concentration, and expected P&L across all your prediction market positions.
Open tool →Why Use These Tools?
Prediction markets price event contracts between $0.01 and $0.99, where the price roughly equals the market's implied probability. But raw prices don't tell the whole story — platform fees, your own probability estimates, and position sizing all affect whether a trade is actually profitable.
These tools help you make better decisions. The Probability Calculator shows you breakeven prices after fees and expected value for any contract. The Kelly Calculator tells you exactly how much to risk based on your edge. And the Arbitrage Scanner finds guaranteed-profit opportunities across platforms.
All calculations run in your browser — nothing is sent to any server. Bookmark the tools you use most and come back anytime.