Guides

The maths behind betting and casino play, explained without the fluff. Each guide links to the calculators and simulators that put it to work.

• Betting Odds Explained: Decimal, Fractional, American and Implied ProbabilityHow decimal, fractional and American odds work, how to read the implied probability behind any price, and how to spot when a bookmaker's margin is eating your value.6 min read
• Expected Value in Betting: How to Know if a Bet Is Worth MakingWhat +EV means in practice, how to work out the expected value of a bet from your probability and the price, and why closing line value is the honest scoreboard.7 min read
• Bankroll Management for Bettors: Unit Sizing, Staking and DownswingsHow to set a bankroll, size a betting unit, choose between flat and percentage staking, and survive the losing runs that a real edge still goes through.7 min read
• The Kelly Criterion Explained (and Why Most People Use Half)What the Kelly criterion is, the formula for the optimal bet fraction, why full Kelly is so punishing in practice, and how fractional Kelly trades a little growth for far smaller swings.6 min read
• House Edge, RTP and What Casino Games Actually Cost YouWhat the house edge means, how it differs from RTP and hold, why turnover matters more than your buy-in, and which casino games are cheapest and most expensive to play.7 min read
• Do Betting Systems Work? Martingale, D'Alembert and the RestHow the popular staking systems work, why none of them changes the house edge, and what they actually do to the shape of your results.6 min read