House Edge Explained: Expected Cost Is Not a Fee on Every Round
Calculate a standard single-zero example, distinguish turnover from deposits and understand why expected loss does not predict the amount lost in a session.
Published 23 10 月 2026
House edge describes a mathematical disadvantage under specified rules. It is not necessarily an extra charge removed from the balance after every round. A player can win a particular round, or finish ahead for a session, while the game model still has a positive edge for the house. Expected value and an individual result are different quantities.
Build the number from outcomes
Take an idealized, fair single-zero roulette wheel with 37 equally likely pockets. Consider a one-unit wager on a single number paying 35 units of profit when it wins. The winning outcome returns 36 units including the stake; each of the other 36 outcomes returns zero.
The expected gross return is 36 ÷ 37 units. Subtracting the one-unit cost gives an expected net result of −1 ÷ 37, approximately −0.027027 units. On this stake basis, the house edge is therefore about 2.70%. This is a worked model using stated assumptions, not a measured result or an M2 table specification.
An expected cost is not an invoice
Across hypothetical total stakes of 200 units under those same assumptions, expected loss is 200 ÷ 37, about 5.41 units. The actual result need not be a loss of 5.41. A short sequence has discrete wins and losses and can finish on either side of that expectation.
This distinction matters when someone describes a low-edge game as “almost free”. A small percentage applied repeatedly can correspond to substantial turnover. It also says nothing about whether a particular person can afford the possible actual loss.
Use the correct stake basis
If a 50-unit balance is repeatedly reused and total stakes reach 200 units, use 200 for this expected-cost calculation, not 50. A deposit is funding; turnover is the exposure to the game’s repeated outcomes. Do not use a hypothetical expected-loss figure as an estimate of money you will reliably retain.
When can you subtract RTP from 100%?
For a consistent model that measures gross prizes and cost on the same stake basis, house edge is 1 minus expected gross return per unit staked. A theoretical 96% return would correspond to a 4% edge on that basis. The relationship becomes misleading if fees, optional side bets, additional stakes or different definitions are mixed together.
Rules can change the calculation
A different roulette wheel, a modified payout, a special zero rule or a separate side bet requires its own calculation. In decision-based games, a quoted percentage can also rely on a specified way of playing. Do not copy one familiar percentage across every table bearing the same game name.
Use M2 category overview for the site’s live-game category context. The wheel illustration is decorative and does not identify a currently available variant. Understanding expectation is a way to read costs accurately, not a system for removing uncertainty or guaranteeing a profitable session.
