The house edge is what is left when you subtract RTP from 100%. It is not a fee. It is a property of the game, applied to every single wager you make.
The numbers
| Game | Typical house edge |
|---|---|
| Blackjack, played with basic strategy | about 0.5% |
| European roulette (single zero) | 2.7% |
| American roulette (double zero) | 5.26% |
| Slots | 2% to 12% |
| Keno and similar | 25% or more |
The arithmetic that matters
The edge applies to turnover, not to your deposit. This is the point almost everyone misses.
Stake $10,000 in total on European roulette at a 2.7% edge, and your expected loss is:
2.7% of $10,000 = $270.
It makes no difference whether you did that in one bet or in a thousand small ones. It makes no difference whether you bet red, or a single number, or covered a dozen. The edge is applied every time, and expected losses accumulate with turnover.
This is also why turnover is the enemy of a bankroll. A $200 deposit played through fifty times is $10,000 of turnover, and the expected outcome is the loss of $270 — more than the deposit itself.
What variance does and does not do
You will have winning sessions. Sometimes large ones. Variance is real, and in the short run it swamps the edge completely. That is what makes the games playable at all.
What variance does not do is change the expectation. The edge is the direction the water flows. Individual waves go the other way constantly.
If your play has stopped being entertainment, start here.