House Edge, RTP and Hold: Three Numbers That Get Confused

Three percentages often appear in discussions of casino games, and people regularly use them as though they mean the same thing. They don’t. Getting them straight makes it much easier to compare games and to understand what a session is likely to cost.

House edge

The house edge represents the casino’s expected profit as a percentage of each bet. European roulette has a 2.70% edge: for every £100 bet, the casino expects to keep £2.70. It is a per-bet figure, derived from the difference between the true odds of an outcome and the odds the casino pays.

Return to player (RTP)

RTP is simply 100% minus the house edge, expressed from the player’s side. European roulette’s 97.30% RTP and 2.70% edge describe the same thing. Slots quote RTP; table games more often quote edge; both are per-bet, long-run expectations.

Hold

Hold is where confusion starts. It is also the percentage of money that a player brings to the game which the casino ends up keeping. The hold measures the casino’s result over a session, and it is almost always much larger than the house edge because players bet the same money repeatedly.

Imagine bringing £100 to a 96% RTP slot and staking £1 a spin. After 100 spins you’ve wagered £100 and, on average, have £96 left. You keep playing. After 200 spins you’ve wagered £196 in total and have roughly £92. Continue for 500 spins and the expected balance is around £81. The house edge never changed — 4% per spin — but the hold on your original £100 is now 19%.

If you play until you lose all your money, as many people do, the hold reaches 100% regardless of the house edge. The edge determines how long that takes, not whether it happens.

Why this matters

Comparing games. House edge or RTP is the right measure for comparing games, because it’s independent of how long you play. Hold depends on behaviour.

Understanding cost. For an individual player, the realistic cost of a session is closer to the hold than to the edge. A 4% edge feels small; the fact that it compounds with every re-bet is what makes casinos profitable.

Reading marketing. “Only a 1% house edge” on a game that deals 100 hands an hour at £5 will, on average, cost £5 per hour. “4% edge” on a slot at 10p spins, 300 spins an hour, costs £1.20 per hour. Edge alone doesn’t tell you the hourly cost; edge × stake × speed does.

Turnover, the missing link

The number that connects edge and hold is turnover — the total amount staked. Expected loss = turnover × house edge. Two players with the same budget and the same game have completely different expected losses if one bets three times as often. This is why stake size and session length, not game choice alone, determine what play costs.

Putting it together

• Use RTP / house edge to choose between games.
• Use stake × bets per hour × edge to estimate hourly cost.
• Recognise that hold — what actually leaves your pocket — is a function of how long you keep the money in motion.

Once you see the three as a chain rather than as synonyms, most casino maths becomes straightforward.

Every casino game has an edge. Choosing a low-edge game slows the rate of loss; deciding in advance when to stop is what limits it.