What is Volatility Index?

A volatility index is a studio's own rating of how a slot pays — usually one to five, or low/medium/high. It describes the shape of the distribution, not its size: RTP says how much comes back over millions of spins, volatility says whether it returns in frequent small wins or rare large ones. It matters most when a bonus is involved. High-volatility games swing hard enough to clear a wagering requirement in one session or lose the balance in twenty spins; low-volatility games grind the requirement down slowly and predictably. Casinos know this, which is why the games excluded from bonus play are almost always the high-volatility ones. Read the index as the studio's claim rather than a measured figure. Two games rated 5/5 by different studios are not comparable, and the same game can carry different ratings on different casinos' game cards.