House edge, explained with real numbers
The house edge is the percentage of every bet the casino expects to keep over the long run. On European roulette it's 2.70%, meaning that for every 100 staked, the casino expects to hold 2.70 regardless of who is playing. It isn't a fee taken from your balance — it's priced into the payouts themselves.
WagerSave Editorial·Updated ·6 min read·The MathsThat distinction is the whole thing, so let's build it from a roulette wheel.
Where the 2.70% is hiding
A European wheel has 37 pockets: 1 to 36, plus a single zero.
Bet on a single number and the true odds of hitting are 1 in 37. A fair payout — one that makes the bet break even over time — would be 36 to 1. The casino pays 35 to 1.
That one-slot difference is the entire margin.
Over 37 spins of 1 unit each, betting the same number every time:
Staked: 37 units Expected wins: 1 (paying 35 + your 1 back = 36 units) Returned: 36 units Shortfall: 1 unit
One unit lost on 37 staked. 1 ÷ 37 = 2.70%.
No money was deducted. No commission was charged. The payout was simply one notch short of fair, every single time, and the shortfall compounds silently across every bet placed.
Add a second zero — the American wheel, 38 pockets — and the same 35-to-1 payout now sits two notches short of fair. 2 ÷ 38 = 5.26%. Identical game, identical payout table, nearly double the cost.
Where that margin ends up: How casino cashback actually works.
The number is per bet, not per session
This is the most common misreading. A 2.70% edge does not mean you'll finish the night down 2.70%.
Play 100 spins at 10 a spin and you've staked 1,000. Expected loss is 27. Your actual result will be almost anything but 27 — you might be up 340, down 610, up 20. Variance dominates over any realistic number of spins.
What the edge tells you is what happens as the sample grows. Over 100 spins it's a rounding error against the noise. Over 100,000 spins across every player on the floor, it's the casino's revenue line, accurate to within a fraction of a percent.
The casino isn't gambling. You are. The casino is running a volume business on a known margin, and the only thing it needs is for enough bets to be placed.
Related: Volatility vs house edge.
Real numbers across real games
The spread between the top and bottom of that table is roughly 30x. Same 1,000 staked, thirty times the expected cost depending on where you put it.
Two things follow. Blackjack at 0.50% is by a distance the cheapest way to put volume through a casino — and, for exactly the same reason, close to worthless for earning cashback, because there's almost no margin to rebate. And the baccarat tie bet at 14.36% should be treated as a donation.
House edge and RTP are the same number
RTP — return to player — is just the edge stated from the other direction.
House edge = 100% − RTP RTP = 100% − House edge
A 96% RTP slot has a 4% house edge. A 99.5% RTP blackjack game has a 0.5% edge. Slots almost always advertise RTP because 96% reads better than 4%; table games usually quote edge.
Same figure, different marketing.
RTP isn't what you think it is covers why the published number is measured over millions of spins and what that means for your session.
What the edge doesn't account for
Player skill, where it exists. Blackjack's 0.50% assumes flawless basic strategy on every hand. Play by instinct and the real edge you're facing is closer to 2%. Video poker is similar — the quoted figures assume optimal holds. Slots, roulette and crash have no skill component; the edge is the edge.
Side bets. Almost universally carry a much higher edge than the base game. A blackjack table advertising 0.50% may be running insurance and perfect-pairs side bets at 5–8%.
Bet-size variation. The edge is a percentage of turnover, so a player betting 100 a hand pays twenty times what a player betting 5 pays over the same number of hands.
Rebates. Cashback reduces the effective edge without eliminating it. A 4% slot with a rebate returning 1.6% of turnover leaves you facing an effective 2.4%. Better. Still negative.
Why this matters if you're chasing cashback
Cashback is calculated as a share of the house edge, which produces a genuinely uncomfortable result: the games that cost you least generate the least cashback, and the games that cost you most generate the most.
Over 10,000 wagered at a 10% rate:
Cashback should never change which game you play. If the rebate is what makes a high-edge game look attractive, the arithmetic has gone somewhere wrong. Pick the game you want to play, then make sure your turnover is tracked.
Frequently asked questions
What is a good house edge?
Anything under 1.5% is favourable by casino standards — blackjack, baccarat banker, and 1% crash games all qualify. Above 5% you're paying a lot for the entertainment. Mystery boxes and lottery-style products sit far higher.
Can you beat the house edge?
Not on games of pure chance. No betting system, progression or pattern changes the maths, because each result is independent and every payout is already priced short. Advantage play exists in a narrow band of games under conditions casinos actively remove.
Is a 96% RTP slot good?
It's around average for online slots. 97%+ is above average, below 95% is poor. The figure is a long-run average across millions of spins and says nothing about any individual session.
Does the house edge change with bet size?
No. It's a fixed percentage of whatever you stake, so larger bets cost proportionally more in expectation, not more per unit.
18+. Every game listed here has a negative expected return. Cashback reduces the house edge; it does not remove it. If gambling stops being entertainment, find support.