Slot volatility explained: why two 96% slots play so differently

Two slots can return almost the same share of stakes over time & still behave in very different ways, because volatility describes how often a game pays & how much.

What slot volatility means

Volatility is about the shape of a slot’s wins rather than their total.

Wazdan also says that “Traditionally, volatility in online slots was fixed at the design stage and remained unchanged.” The studio sells a feature, Volatility Levels, that lets players adjust volatility within a game.

The UK Gambling Commission treats volatility as a measurable statistic. In its guidance on monitoring games, it expresses a game’s volatility as a “standard deviation”, a measure of how widely results spread around the average.

Low vs high volatility

According to Wazdan, games with low volatility “deliver wins more often, but these tend to be smaller”. High-volatility games, it says, “offer wins less frequently, but the payouts can be much larger”.

Studios label games on their own scales. Nolimit City says its San Quentin 2: Death Row, released on 24 September 2024, “operates on an Insane volatility model”, with the top prize “capped at a maximum win of 200,000x your initial wager”.

On its game page, Nolimit City also describes the game’s mathematical engine as “incredibly unforgiving”. The page lists minimum & maximum bets of €0.20 & €100.00.

Volatility vs RTP

RTP, or return to player, is the share of money staked that a game pays back as wins. The UK Gambling Commission says actual RTP is found by dividing wins by turnover, so a game with £1,085,000 in wins on £1,200,000 of turnover has an actual RTP of 90.42%.

RTP & volatility measure different things. NetEnt’s Starburst page lists a 96.08% RTP & a top payout of 800 times the bet, on a 5 x 3 grid with up to 10 play lines.

Nolimit City lists San Quentin 2 at a 96.13% RTP, a top payout of 200,000 times the bet & a probability of reaching that maximum win of 1 in 1.5m. The two RTPs are 0.05 points apart, while the top prizes differ 250-fold.

RTP describes the long run. The UK Gambling Commission says that “After a significant amount of plays the actual RTP should be very close or equal to the theoretical RTP.” Volatility describes how that return is spread along the way.

The two can be set separately. Wazdan says its adjustable volatility feature “does not affect game’s RTP”.

Hit frequency: how often a spin pays

Studios also publish a hit frequency for each game. NetEnt lists 23.00% for Starburst, & Nolimit City lists 26.90% for San Quentin 2, which also lists free spins at 1 in 299.

Neither studio page defines the term in the text reviewed here. Researchers at the University of Waterloo, Dixon et al., use a related measure, tabulating “the percentage of spins that result in wins” alongside losses.

The two published hit frequencies are close, yet they sit beside top payouts of 800 & 200,000 times the bet. A hit frequency says how often something is paid, not how large the payment is. The pages reviewed here do not say whether a payout smaller than the stake counts as a hit.

When a win is really a loss

On modern slots, “Players can wager on multiple lines”, according to a 2010 study by Dixon et al. in the journal Addiction, available from the University of Waterloo. The authors found that winning sights & sounds also play “when the amount won is less than the spin wager”.

They call these outcomes “losses disguised as wins”, or LDWs. In the paper’s example, a player stakes 75 credits across 15 lines, “wins” 25 credits & is 50 credits, or $2.50, down on the spin.

LDWs became more frequent as more lines were played, & “when 15 lines are played, the LDWs actually outnumber the wins”.

In tests on 40 novice players, the study found skin conductance responses, a measure of physical arousal, were similar for wins & LDWs, & both were larger than for regular losses.

In Great Britain, the UK Gambling Commission’s technical standard RTS 14F applies to casino games. It states: “The gambling system must not celebrate a return which is less than or equal to the total stake gambled.” The guidance defines celebrate as the use of auditory or visual effects associated with a win.

Why sessions swing

Volatility governs how far actual results can stray from RTP. The UK Gambling Commission’s guidance on live RTP monitoring says “the volatility of the game must also be considered as it will inform the allowable tolerance above or below the theoretical RTP”.

These ranges use a 95% confidence level.

The Commission adds that a game designed at 91.68% RTP, after 400,000 games, “could return between 89.93% and 93.43% and still be considered to be performing as expected”. Even then, it says, “a non defective game might still fall outside range approximately 1 in 20 tests”.

A single player’s session is far shorter than these samples. The Commission says that measuring a game with only a small amount of play “will be pointless as the tolerance will be too large for meaningful results”.

Stake limits & speed rules in Great Britain

According to the UK Gambling Commission’s stake limit guidance, the £5 limit for all adults went live on 9 April 2025 & the £2 limit for adults aged 18 to 24 went live on 21 May 2025.

The limit applies per game cycle, which the regulations define as running from the start of a game until all money staked has been lost or all winnings have been made available to the player. The Commission says the limits are for online slots only & do not apply to games such as roulette or blackjack.

Speed is also regulated. Under RTS 14D, “It must be a minimum of 2.5 seconds from the time a game is started until the next game cycle can be commenced.” Under RTS 14E, “Features such as turbo, quick spin and slam stop are not permitted”, & RTS 14C bars functionality that lets a customer play multiple games at the same time.

As the Commission’s tolerance tables show, results over a short stretch of play can differ widely from that average.

Questions

Does a high-volatility slot have a lower RTP?

Not necessarily. Nolimit City describes San Quentin 2 as “Insane” volatility with a 96.13% RTP, while NetEnt lists Starburst at 96.08%, & Wazdan says its adjustable volatility feature does not affect RTP.

What is a loss disguised as a win?

It is a spin where a slot shows a win but pays back less than was staked, a term used by Dixon et al. in a 2010 study. They found these outcomes outnumber real wins when 15 lines are played on Lobstermania.

How much can be staked on an online slot in Great Britain?

According to the UK Gambling Commission, the limit is £5 per game cycle for adults aged 25 & over, live from 9 April 2025, & £2 for 18 to 24 year olds, live from 21 May 2025.

Why can results differ so much from a game’s RTP?

RTP is a long-run figure, & the UK Gambling Commission says the allowable gap between actual & theoretical RTP depends on volatility & narrows as play increases.

Sources

• yogonet.com
• netent.com
• nolimitcity.com
• uwaterloo.ca
• gamblingcommission.gov.uk
• gamblingcommission.gov.uk
• gamblingcommission.gov.uk

Sources checked 30 October 2026. Information only. 18+.