What is volatility (variance)?
Definition and example from our casino glossary.
Definition
Volatility describes how widely results swing around the average: high-volatility games pay rarely but larger amounts, low-volatility games pay often but smaller amounts.
Two slots with identical RTP can feel completely different because of volatility. In a low-volatility game, much of the return is spread across frequent small wins, so a balance tends to fall slowly and evenly. In a high-volatility game, a larger share of the return is concentrated in rare features and top prizes, so most sessions end below the starting balance while a few end well above it. Statistically, volatility relates to the standard deviation of outcomes per bet. Providers rarely publish that number and instead use labels such as low, medium or high, sometimes on a five-point scale, which are not standardised between studios. Volatility does not change the house edge, but it does change the risk of losing a budget quickly. A high-volatility game needs a larger bankroll for the same number of spins, or a smaller stake if you want the session to last.