Illustrative odds — shown to explain formats, not to place bets.
Every game in an online casino resolves the same way: you choose a stake, the game produces an outcome, and a published paytable decides what that outcome returns. The outcome itself comes from a random number generator — a piece of software that picks a result the instant you press the button, independently of every round that came before it.
The catalogue is usually split into three formats that behave quite differently, even though they sit behind the same account and the same balance.
RTP — return to player — is the share of everything staked that a game pays back across millions of rounds. A 96% RTP means that in the long run the game keeps 4 units of every 100 staked. That 4% is the house edge, and it is the same number seen from the other side.
RTP is a long-run average, not a schedule. It says nothing about your session, your hour or your next hundred spins. Results are produced by a random number generator, and each round is independent: the game has no memory of the last one and no obligation to balance it.
Volatility describes the shape of the ride. Two games can share the same RTP while one pays small amounts often and the other pays rarely and large. Higher volatility means longer losing stretches between results — which is precisely when a session budget stops being theoretical.