House edge explained: what the casino actually keeps

What the house edge is

The house edge is the average share of each bet the house expects to keep, over a long run of bets. An edge of 1% means that for every 100 credits wagered, the house expects to end up with 1, and you expect to end up with 99.

Its mirror image is RTP, return to player. RTP is simply 1 − edge. A 1% edge is a 99% RTP. A 10% edge is a 90% RTP. They are the same fact stated from the two sides of the table, and knowing one gives you the other.

The important word is average. The edge is not a fee deducted from each bet. Individual rounds pay out or they do not. The edge is what remains once enough rounds have been played for luck to cancel itself out.

Where the edge hides

In most games the edge is not a separate charge. It is baked into the payout, as a small gap between what a bet pays and what it would pay if the game were fair.

Roulette is the clearest example. A single number on a European wheel has a 1-in-37 chance of landing. A fair payout would be 36 to 1. The table pays 35 to 1. Nothing is deducted, nothing is announced, and the whole edge lives in that missing unit — about 2.7%. An American wheel adds a second zero, making the chance 1 in 38 while still paying 35 to 1, which is where its 5.26% comes from.

Every other game does a version of the same trick. The odds of the event and the price paid for it are pulled slightly apart, and the gap is the business.

Typical house edges

Two things jump out of that table. The first is the spread: the worst common bet is fifty times harsher than the best one. The second is that the games with the loudest presentation are usually the ones with the largest cut.

Why a small edge is not a small number

A 1% edge sounds survivable. It is, on one bet. The problem is that the edge applies to turnover, not to your deposit, and turnover grows every time you re-bet money you have already won.

Say you sit down with 100 credits and place 1-credit bets on a 1% edge game. Playing 100 rounds puts 100 credits through the game, and the expected cost is 1 credit. Playing 5,000 rounds — a couple of hours on a fast game — puts 5,000 credits through it, and the expected cost is 50: half your bankroll, from a number that looked like a rounding error.

This is why the edge is quoted per bet and felt per session. The house does not need a big cut. It needs a small one and enough repetitions, and the repetitions are the part the design of the game controls.

What the edge does not tell you

The edge sets the destination, not the route. Two games with an identical 1% edge can feel nothing alike, because volatility — the size and rarity of the wins — is a separate dial.

• A low-volatility game pays small and often. Sessions drift rather than swing, and results converge on the theoretical RTP quickly.
• A high-volatility game pays rarely and large. Most sessions end below average, funded by the rare ones that end far above it.
• Both can be set to the same long-run return. The edge says how much you lose over time; volatility says how loudly.

This is why chasing a game because it "feels loose" tells you nothing. The feel is volatility. The cost is the edge, and it does not appear on the surface at all.

Strategies that cannot beat it

A negative-expectation game stays negative regardless of how bets are ordered or sized. This is not an opinion about discipline; it is arithmetic. The expected value of a sequence of bets is the sum of their expected values, and adding negative numbers in a clever order does not change the sign.

1. 01Martingale. Doubling after a loss converts many small wins into one catastrophic loss. The expected value is unchanged; only the shape of the distribution moves. Table limits and finite bankrolls guarantee the tail eventually arrives.
2. 02Due numbers. Independent rounds have no memory. A roulette wheel that has landed red ten times has exactly the same odds on the eleventh spin.
3. 03Cash-out timing. On games where you choose an exit multiplier, the win chance moves in exact proportion to the payout, so every target returns the same expected value.
4. 04Bet sizing. Larger bets lose more per round, smaller bets lose less. The percentage is identical.

The one real exception in a real casino is advantage play — card counting in blackjack, where the deck's composition changes the edge as cards are removed. It works because the game has memory. Almost nothing else does.

Seeing the edge instead of reading about it

The gap between understanding the edge and believing it is usually experience, and the experience is expensive to buy at a real table. This is the entire reason LarpCasino exists.

It is a simulated casino for iPhone with no real money in it. Credits are invented, nothing can be deposited or cashed out, and the house edge is a slider you control from −100% to +100%. Every game prints the odds it is running at, and four presets cover the interesting territory:

Set the edge to 10%, play a few hundred rounds, and the drift stops being theoretical. Set it to −3% and watch a bankroll grow for the same structural reason a real one shrinks. Then open the RTP simulator and run a million rounds in the time it takes to read this paragraph.

The short version

• The house edge is the share of every bet the house keeps on average. RTP is what is left.
• It is hidden in the gap between true odds and paid odds, not charged as a fee.
• It applies to everything you wager, so it compounds with time at the table rather than with your deposit.
• Volatility changes how a session feels. Only the edge changes what it costs.
• No betting system beats a negative edge, because ordering negative numbers does not make them positive.