Volatility
RTP tells you where the average sits. Volatility tells you how far results scatter around it — and over a session, the scatter matters far more than the average.
Two games can both return 96% over the long run and feel nothing alike. One pays small amounts often; the other pays almost nothing for long stretches and occasionally pays a great deal. The published RTP is identical. The experience is not.
Volatility is the name for that difference. Formally it is the variance of the return per unit staked — how widely individual results spread around their mean. It is entirely independent of RTP: you can hold the long-run return fixed and move the volatility anywhere you like, simply by making wins rarer and correspondingly larger.
Why they are independent
Take a simple game: each stake returns k times the stake with probability p, and nothing otherwise. Its RTP is p × k.
RTP: r = p × k
Variance per unit staked: r² × (1 − p) ÷ p
Standard deviation per unit staked: r × √((1 − p) ÷ p)
Hold r fixed and lower p. To keep p × k constant, k must rise — wins get rarer and bigger. The RTP has not moved and the variance has risen sharply. That is the whole relationship.
What that looks like in numbers
Standard deviation per unit staked at a fixed 96% RTP, as the hit frequency falls. The long-run return is identical in every row.
| Hit frequency | Win pays | SD per unit staked | Character |
|---|---|---|---|
| 50% | 1.92× | 0.96 | Frequent small results |
| 25% | 3.84× | 1.66 | Moderate |
| 10% | 9.60× | 2.88 | Long gaps between wins |
| 2% | 48.00× | 6.72 | Rare, large wins |
| 0.5% | 192.00× | 13.54 | Very rare, very large |
Why this matters for a wagering requirement
The expected balance calculator reports an average. On a low-volatility game, most real results land somewhere near it. On a high-volatility game, most land well below it, and the average is held up by a small number of outcomes that land far above.
That has a practical consequence for clearing a requirement. High volatility raises both the chance of busting before you finish and the chance of finishing well ahead. It does not change the expected cost by a single coin — the house edge is untouched — but it widens the range of things that can happen on the way.
The variance explorer simulates exactly this, from a seed you can reuse.
Two things volatility does not mean
It is not a strategy. Choosing a high-volatility game does not improve your expected result. It changes the shape of the distribution around an expectation that stays exactly where it was.
It does not create a debt. A game that has paid nothing for a long stretch is not “due”. Each play is independent, and nothing about the published RTP or the volatility makes a game owe anyone a result.
Volatility labels
Some studios publish a low/medium/high label for their games. Where one exists and is sourced, this site records it. It is a rough guide rather than a measurement: the labels are not standardised between studios, and a “high” game from one maker may spread less than a “medium” from another. This site does not invent a label for a game whose maker has not published one.