Part III: Business & Regulation · Gambling Mathematics & Probability

5. House Edge (House Advantage)

Foundational Probability

The house edge is the mathematical advantage expressed as a percentage that the casino holds over the player on any given bet, representing the average percentage of each wager that the casino expects to retain over the long term. It is calculated as the ratio of the expected player loss to the initial wager. For example, a house edge of 5.26% on American roulette means the casino expects to earn $5.26 for every $100 wagered over millions of spins. The house edge is the single most important metric in casino game design and operations — without it, the casino would not be a viable business. Surveillance professionals monitor for advantage play techniques that can reduce or eliminate the house edge.

In practice

The house edge varies dramatically by game and bet type — from 0.5% on blackjack with basic strategy to over 25% on keno. The terms “house edge” and “house advantage” are interchangeable. Formula: House Edge = (Expected Loss per Bet) / (Initial Wager) x 100%.

One entry from the Casino Industry Glossary — 1,157 terms written for surveillance, compliance and operations professionals rather than for players. Definitions describe industry usage; where a term carries a regulatory meaning, verify against the instrument that governs your jurisdiction.