Infinity Reels explained

What Infinity Reels is

Most slots have a fixed number of reels. Infinity Reels slots don't: in these games, extra reels are added when a winning combination lands. A winning spin widens the grid, giving later results more room to connect, and the game keeps growing for as long as the wins continue. How a sequence ends, and whether any added reels carry into a bonus round, is set by each title, so the help screen is the place to confirm the details.

The mechanic is ReelPlay's, and the name is a trademark. According to coverage of ReelPlay's licence deal (opens in a new tab), Infinity Reels launched in November 2019. It sits alongside other grid-changing mechanics in our slot features guide, such as Megaways and cascading reels.

Infinity Reels history and licensed games

ReelPlay is a small studio, so the mechanic has spread largely through partnerships. In December 2020 Scientific Games, which is now Light & Wonder, licensed Infinity Reels, with Book of Ultimate Infinity as the first title under the deal; Scientific Games had earlier helped develop El Dorado Infinity Reels. In July 2021 Yggdrasil released Martian Miner Infinity Reels, the first title from BB Games to use the mechanic, as reported in iGaming Business's report on Martian Miner Infinity Reels (opens in a new tab).

We don't yet have reviews of individual Infinity Reels slots with verified specifications, so we don't quote RTPs or max wins for these titles here. Check each game's help screen for its figures. For the studios involved, see our pages on Light & Wonder and Yggdrasil.

How an Infinity Reels sequence plays out

The details vary by game, but the pattern described by developers and launch coverage looks like this.

1. You place a stake and spin the starting set of reels.
2. If the spin produces a winning combination, the win is paid and an extra reel is added.
3. The wider grid gives symbols more room to connect, so the next result can include longer wins.
4. In some titles, such as Book of Ultimate Infinity, a multiplier also rises as reels are added.
5. The sequence ends under the game's own rule, and the grid returns to its starting size for your next paid spin.

This is close in spirit to a cascade: one win leads to another chance at no extra stake. The difference is that a cascade removes and replaces symbols on a fixed grid, while Infinity Reels changes the size of the grid itself.

Infinity Reels maths: how extra reels multiply the ways

The appeal of the mechanic is how fast the possibilities grow. If a game pays on adjacent symbols across reels of three rows, which is a common ways-to-win structure, each extra reel multiplies the number of ways by three. This is an illustration of the arithmetic; check each game's help screen for its actual pay structure.

For comparison, many Megaways games reach up to 117,649 ways, and Nolimit City's Misery Mining, whose grid expands from 3×3 to 7×7, runs from 27 up to 823,543 ways, which is 7 multiplied by itself seven times. More ways don't mean more value, though. The game's maths balances symbol pays against the number of ways, and the overall return is fixed by the RTP. Our page on ways to win explains how ways are counted.

Why long Infinity Reels chains are rare

Reaching a wide grid needs several wins in a row. Studios don't publish the chance of each extension, so the figures below are invented purely to show the shape of the maths. If each step had a 40% chance of producing another win, the chance of adding at least k reels would be 0.4 multiplied by itself k times.

In a real game, the chance of the next win usually rises as the grid widens, because there are more ways to connect, so the drop-off may be gentler. The principle holds, though: the very wide grids shown in promotional clips come from rare chains, and most spins end on the starting reels. That concentration of value in rare sequences is what pushes up volatility, and our primer on casino probability explains why multiplying chances shrinks them so fast.

Infinity Reels compared with other expanding mechanics

Nolimit City's xWays and xNudge and Yggdrasil's GigaBlox change the grid in other ways again. If you like the build-up of Infinity Reels, these are worth comparing, keeping in mind that each is designed to deliver the same kind of uneven, feature-driven returns.

What Infinity Reels means for a £20 budget

A slot's long-run cost is stake × house edge. If an Infinity Reels title has a 96% RTP, which you should confirm in the game, the house edge is 4%: about 0.4p a spin at 10p, 2p at 50p and 4p at £1. On £20, that is 200 spins at 10p, 40 at 50p or 20 at £1 before any wins come back.

Because much of the return sits in occasional long chains, a short session can feel thin. A smaller stake gives you more spins and a better chance of seeing what the mechanic does before the budget runs out. Our answer to how long £20 will last on a slot goes further.

UK rules for Infinity Reels slots

Infinity Reels games follow the same British slot rules as any other. The Commission's RTS 14 product design standard (opens in a new tab) requires at least 2.5 seconds per slot game cycle, bans turbo and slam stop, and forbids celebrating returns at or below the stake. Autoplay is banned. Stakes are capped at £5 a spin for players aged 25 and over and £2 for those aged 18 to 24. See our pages on UK game design rules and slot stake limits.

Since a Gambling Commission warning in January 2020, feature buy-ins are not offered to British players, so any buy option an overseas version of a title may have won't appear here; our bonus buy page explains why.

Where to play Infinity Reels slots

Our partners' offers are slot offers paid as 10p spins on set or selected games; we can't confirm which casinos list Infinity Reels titles, so check each casino's game lobby. 18+ and terms apply.

• PlayOJO: new UK customers, excluding Northern Ireland, get 80 free spins on Big Bass Bonanza at 10p each with a first deposit of £10 or more. No wagering applies and winnings are paid in cash; the offer can't be combined with others and is available only through the designated offer link.
• Coral: new players who deposit (certain methods excluded) and bet £10 or more on slots from 1 October 2026 to 1 February 2027 get 100 free spins on selected games at 10p each, which must be accepted within 48 hours and used within 7 days, with no wagering on winnings. Qualifying deposits can't come from Neteller, PayPal, Paysafe, Skrill, a prepaid card or certain debit cards.
• Ladbrokes: new customers who deposit and spend £10 or more on slots get 50 free spins a day for 10 days, up to 500 in total, at 10p each on selected games, claimed before 23:59 each day and valid for 7 days, with no wagering. PayPal, Paysafe, Neteller, Skrill, Moneybookers and prepaid card deposits are left out.

Coral and Ladbrokes are both LC International Limited brands, so one person may not be able to open new accounts at both. See our Ladbrokes casino review for its wider terms.

18+. Every casino game has a built-in house edge, so over time you should expect to lose what you stake. Set a budget before you play and stop when it’s gone: safer gambling tools and support. Free, confidential help: National Gambling Helpline 0808 8020 133.