RTP versus volatility: what each figure measures and where it stops

Two figures sit at the top of nearly every SlotSpecs spec sheet: RTP and volatility. One describes how much a game hands back in the long run; the other describes how lumpy that hand-back is. Neither describes your next session. That is the verdict in a sentence, and it runs against how the numbers are usually read, with RTP treated as a promise and volatility as a vague feeling. Below, James Cooper takes both apart with plain arithmetic and real specs from the database, showing what each figure measures and where it stops being useful.

Return to player, defined carefully

RTP is the proportion of all money staked that a game is built to pay back across an extremely large number of rounds. Gambling Commission consumer guidance stresses the key condition: the figure is an average reached over a significant number of plays, not on every play. Its own illustration uses a machine displaying 85% RTP and warns that a player should not expect that share of each stake back within one session.

The phrase people skim past is "extremely large". RTP belongs to the maths model and is calculated from every possible outcome weighted by its probability. A few hundred spins sample only a sliver of that model, and a sliver can look nothing like the whole.

UK standards require information on the likelihood of winning, for example the RTP or the probability of winning events, to be easy to find before play starts. RTS 3C names the average theoretical RTP as one acceptable way to satisfy that rule, which is why the figure normally appears in a game’s info screen.

The sum for 1,000 one-coin spins

The Dog House Megaways 1000 has a default RTP of 96.5%. Picture 1,000 spins at 1 virtual coin apiece.

• Staked in total: 1,000 coins.
• Average long-run payback at 96.5%: 965 coins.
• Average long-run amount the game keeps: 35 coins, the 3.5% house edge.

The 965 is an average over a vast number of imagined 1,000-spin sessions. It is not a forecast for any one of them. Plenty would finish well short of 965 and some well beyond it, because much of this game’s return sits in rare wild combinations and bonus rounds. The review cites a published free spins frequency of about 1 in 388 spins, so a 1,000-spin sample might hold two or three bonus rounds, or none at all, and those rounds by themselves can move the outcome by hundreds of coins in either direction.

Read honestly, 96.5% means "taken across all possible play, this design pays back 96.5% of stakes". It does not mean "I will receive 965 coins".

One title, several return settings

Many studios build a single game at several RTP settings and leave the choice to whoever distributes it. The database has plenty of cases:

Artwork, rules and features do not change between settings. Only the hidden weighting does. Take the Eye of Horus range with 10,000 coins staked over the long run:

• The 96.31% setting pays back 9,631 coins on average.
• The 88.26% setting pays back 8,826 coins on average.

That is 805 coins apart for every 10,000 staked, on a game that looks exactly the same. The setting in use is normally given in the game’s help or info screen, and that figure outranks any list. SlotSpecs displays the default published figure, and where the relevant figure is unclear the page says so instead of choosing the highest.

When a game quotes two RTPs at once

Most RTP figures cover the entire game, base spins and features combined. A handful of games publish different figures for different modes. Lucky Pharoah gives 94% for the base game and 96.25% while Power Spins are running. These are not two versions; it is one game whose optional mode is designed to pay back more of each stake. The database records 94%, the base-game figure.

Special stake modes behave in a comparable way. Ante bets and feature purchases in titles such as Sweet Bonanza 2500 alter both the cost of a spin and how often the bonus arrives. Studios do not always publish an RTP for each option, and the feature purchase guide explains why assuming every mode matches the headline number is unsafe.

Volatility describes distribution

Volatility, also called variance, measures how unevenly a game spreads its RTP. Two games can each pay back 96% over the long run and still behave completely differently on the way there.

• Low volatility games pay out their share in frequent, moderate wins. Outcomes stay closer to the average and long dry spells are rarer.
• High or extreme volatility games reserve much of their return for rare, big outcomes. Most spins pay little or nothing, and the average is lifted by results that many sessions never reach.

No single industry formula defines the label. Each studio picks its own scale, and databases sometimes contradict the studio. Pragmatic Play gives no volatility rating at all for The Dog House Megaways 1000, so the SlotSpecs entry leaves the field empty rather than borrowing someone else’s label.

Four games, four labels

Only 0.05 percentage points of RTP separate Pirots 5 and Duck Hunters, yet the first is rated Medium-High and the second Extreme. The max win column hints at the reason. A game able to pay 30,000x the bet must pay for that possibility somewhere, and it does so by thinning out ordinary spins. With a reported hit frequency of 17.07%, Duck Hunters returns something on fewer than one spin in five.

Plinko+ offers a useful contrast. Pragmatic Play rates it Low, but according to its review the top 1,000x bucket only appears on the 16-line high-risk board. The player’s own choices change how uneven the results are, which is typical of instant games and is covered in the crash games guide.

Hit frequency adds a third dimension

When a studio publishes it, hit frequency shows how often a spin pays anything. Sweet Bonanza 2500 gives roughly 1 in 2.33 spins (42.9%), and Gates of Olympus 2500 roughly 1 in 3.58 spins (27.93%).

A hit is not a profit. Plenty of hits pay less than the stake, which explains how a high hit rate can coexist with high volatility. Researchers call celebrated sub-stake returns "losses disguised as wins", and the UK regulator has banned such celebrations in licensed slots.

Table games and strategy-dependent figures

Table games in the database tend to post higher figures, with Premium Blackjack at 99.58% and Baccarat at 98.94%. In blackjack the number rests on decisions. UK guidance says that where skill is involved, RTP should be worked out using the automatic strategy or a standard published one. Anyone who strays from that strategy is not playing the game the figure describes, so the listed RTP is a ceiling reached through good decisions, not a guarantee.

Four misreadings, corrected

• "97% beats 94%, so it is safer." In the long run it keeps a smaller slice of each stake, but over a short session volatility can easily swamp a three-point difference.
• "It is running under its RTP, so it has to catch up." In a random game earlier rounds have no influence on later ones, which is precisely why the Gambling Commission distinguishes random machines from compensated ones.
• "Low volatility is low risk." It means smoother results. The house edge remains, collected in smaller and more frequent bites.
• "Every studio uses the same volatility scale." None does. Compare labels within a single studio’s catalogue and treat third-party labels cautiously.

RTP and volatility questions

Sources

• gamblingcommission.gov.uk/public-and-players/guide/return-to-player-how-much-gaming-machines…
• gamblingcommission.gov.uk/authorities/guide/page/la-bulletin-august-2020-feature-article
• gamblingcommission.gov.uk/standards/remote-gambling-and-software-technical-standards/rts-3-r…
• gamblingcommission.gov.uk/about-us/freedomofinformation/consumer-misunderstanding-of-return-…
• pragmaticplay.com/en/games/sweet-bonanza-2500