Guides
Long-form guides to reading odds, implied probability, removing the vig, arbitrage, exchange commission, lay betting, Polymarket prices and Kelly staking, each with worked examples.
- Arbitrage Betting: The Complete GuideWhat an arbitrage is, how to find one across books and exchanges, how to size stakes for equal profit, and the risks the maths leaves out.7 min read
- Exchange Commission ExplainedHow exchanges charge commission, what it does to the price you get, how to find the bookmaker price it equals, and its effect on arbitrage.7 min read
- Expected Value and the Kelly Criterion for BettorsHow to compute a bet's expected value from a fair probability and a price, and how the Kelly criterion turns an edge into a stake.7 min read
- How Polymarket Works: A Complete GuideWhat Polymarket is, how YES and NO shares are priced, who trades them, how markets resolve and pay out, and where it is legal. Written for new users.17 min read
- How to Read Betting Odds (American, Decimal, Fractional)What each odds format says, how to convert between them by hand, and the two questions every price answers: what it pays and how likely it is.7 min read
- Implied Probability ExplainedHow to turn any price into a probability, why a market's probabilities exceed 100%, and how to judge whether a price is worth taking.7 min read
- Lay Betting MathWhat a lay bet is, how liability and profit work, why a lay at L is a back at L/(L−1), and how that lets you hedge bookmaker bets exactly.7 min read
- Multiway Arbitrage and Devigging (3-Way, Outrights, Fields)How arbitrage and devigging change with three, six or fifty outcomes: n-leg stakes, where large overrounds hide, and settlement traps.7 min read
- How Polymarket Prices Work as OddsWhat a 64¢ YES share actually means, how to turn it into decimal or American odds, why YES + NO isn't always 100, and how fees change your real price.8 min read
- Polymarket vs Sportsbook ArbitrageHow to find and size an arbitrage between a prediction market and a sportsbook: conversions, fees, stake formulas and the risks.7 min read
- Devig Methods Explained: 5 Ways to Remove VigHow the five common devig methods work, where each one goes wrong, and which to use for 2-way, 3-way and longshot-heavy markets. With worked examples.9 min read