House edge and theoretical win
Every casino game has a return to player (RTP) and a house edge that is its complement. Multiply the house edge by the amount staked and you get the theoretical win: what the game is expected to earn from a player's session.
The formulas
- House edge = 1 − RTP.
- Theoretical win = stake per round × rounds × house edge.
- Actual results swing around the theoretical win; the swing depends on the game's volatility, and it shrinks relative to the stakes only over a very large number of rounds.
Worked examples
- A slot with an RTP of 96% has a house edge of 4%. At 600 spins an hour and a stake of 1, the theoretical win is 24 an hour.
- Single-zero roulette returns 97.30%, a house edge of 2.70%; with a second zero the edge rises to 5.26%.
Operators use theoretical win rather than actual losses to value customers and set rewards, because it does not depend on luck. Related: bonus cost, online casino hub and the glossary.
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