House edge and RTP

One fact, two wordings

The house edge is the fraction of everything staked that the operator keeps over a long run. The return to player is the rest of it. They add up to the whole, so a game described as returning ninety-six per cent has a four per cent edge, and the two sentences say exactly the same thing.

What long run means

Thousands to millions of rounds, depending on the game's volatility. It is not an evening, it is not a week, and it is not a bankroll. A player can lose across a period in which the published figure was met precisely, and can win across one in which it was not — both of those are ordinary rather than surprising.

Volatility is the part that is felt

Two games with the same return figure can behave completely differently. A low-volatility game returns often and in small amounts; a high-volatility one returns rarely and in large ones. The published return figure is identical and the experience is not, which is why the figure alone is a poor guide to what a session will feel like.

Why no RTP figures appear on this site

Because the only authoritative source for a specific game's figure is the information panel inside that game, and a figure repeated from a comparison page is a figure with no source. Operators can also run different configurations of the same title, which means a number that is correct in one place is wrong in another.

More on how any of this works

The rest of how any of this works is below, each page built around one question rather than around a template. The reasoning behind the order of every list here is on the method page, the twelve entries are in the casino index, and the arithmetic that all of it rests on is in the learn section.