The quantitative toolkit for outcome traders
The math doesn't care what platform you're on.
Free calculators and guides for anyone who trades outcomes — sportsbooks, Kalshi, Polymarket, or wherever the edge is.
Prediction Markets
Kalshi, Polymarket, and beyond — fee analysis, EV sizing, liquidity, and portfolio risk.
Market Converter
Convert between sportsbook odds and prediction market prices
Fee Calculator
See how Polymarket and Kalshi fees affect your EV
Break-Even
See how often you need to win after platform fees
PM EV Calculator
Expected value and Kelly sizing for prediction market contracts
Multi-Outcome
Find mispriced outcomes in multi-outcome markets
Liquidity
Simulate order book slippage before placing large orders
Position Risk
See how correlated positions amplify your portfolio risk
Cross-Platform
Compare odds across sportsbooks and prediction markets. Find arbs that survive fees.
Sports Betting
De-vig any line, size your bets, and quantify your edge with real math.
De-Vig Calculator
Remove vig from bookmaker odds — 7 methods compared side-by-side
EV Calculator
Find +EV bets by comparing rec book odds against sharp lines
Odds Converter
Convert between American, Decimal, Fractional and Implied Probability
Kelly Criterion
Calculate optimal bet size based on your edge, odds, and bankroll
Parlay Calculator
Find the true fair odds of your parlay and see the hidden vig
Hold Calculator
See how much vig the sportsbook is charging on any market
What's My Edge?
Test if your betting record shows real skill or just luck
Latest from the blog
Quantitative guides across sports betting and prediction markets.
What Is Vig? The Hidden Tax on Every Bet You Place
Every sportsbook and prediction market charges vig — the built-in margin that guarantees the house profits. Here's how to calculate it and strip it from any line.
Read article →Bankroll Turnover: Why Bet Volume Matters More Than Edge
A 1% edge bet 100 times beats a 10% edge bet once. Here's the math behind turnover rate, compounding, and why volume is the real strategy.
Read article →Closing Line Value: The Best Predictor of Long-Term Profit
Win rate is noise. Closing line value is signal. Here's why the line at market close tells you more about your skill than your actual results.
Read article →