Betting Cost & Session Risk
The book margin is a price per wager, not a one-time fee: expected loss = margin x total wagered. It grows linearly with every bet - the more you bet, the more you pay for the same entertainment. Everything recomputes as you type.
enter values…
session risk - will this bankroll survive the variance?
Expected loss is an average; this models the spread around it. Needs the full game model (win chance + total payout), because a margin alone says nothing about variance. Flat bets, exact binomial end-of-session math. Bet size, bets per hour and hours are mirrored from the cost panel above.
enter the game model…
Reference margins
Esports match-winner moneylines we sampled: 6-8% per two-way market. Live/in-play markets run a point or two higher. Casino "originals" (dice & co) at crypto books: ~1%. European roulette: 2.7%. Slots: typically 2-6%. The lesson is not "never bet" - it is that margin x volume is the real price of the entertainment, and low-margin markets buy you far more playtime per dollar. Compare per-book margins in our comparison table →