Slots on mobile

Slots on mobile: what changes and what doesn't

Modern online slots are built to run in a browser or inside an app on phones, tablets and computers alike, usually using HTML5. The reels, symbols, features and maths are the same whichever device you use. What changes is the layout: buttons move, paytables fold into menus, and some games redesign their screens for an upright phone.

Phones are now a normal way to play. Gambling Commission figures show 60% of online gamblers had used a mobile phone to gamble in 2021, up from 50% in 2019. That makes it worth knowing how slots behave on a small screen and which UK rules apply, which is what this page covers. For other game types, see our mobile casino games hub.

One myth to set aside straight away: an app doesn't secretly lower a slot's RTP. Many slots come in several RTP versions and the casino chooses which to run, so the number to trust is the one in that game's help screen. Our page on whether RTP is the same on mobile explains this in detail.

Paylines, ways, Megaways and cluster pays on a phone

Every slot has a rule for what counts as a win. Classic slots pay along set lines; newer formats pay for matching symbols on adjacent reels, for clusters, or for symbols anywhere on the screen. This plain-English guide to slot features (opens in a new tab) covers the vocabulary, and the table shows where the big numbers come from.

Not every Megaways game reaches 117,649 ways; the maximum depends on its reel count and rows. Our Megaways slots on mobile page covers that format, and Rainbow Riches Megaways is a worked example ranging from 324 to 117,649 ways.

Slot features explained: wilds, free spins, cascades and more

• Wilds replace other symbols, usually except scatters, to help complete a win. Whether they also replace bonus symbols varies by game.
• Scatters pay or trigger features regardless of where they land, and landing a set number usually starts free spins.
• Free spins are bonus rounds played without a further stake. The number needed to trigger them, and any retriggers, depend on the game.
• Cascading reels remove winning symbols and drop new ones in from above, so one spin can produce several wins in a row.
• Multipliers multiply a win: a 5x multiplier turns a £2 win into £10. Ranges are specific to each game.
• Hold and win locks certain symbols in place while other positions respin, giving more chances to add to the feature.

Two features cause confusion in the UK. Feature buys: since a Gambling Commission warning in January 2020, feature buy-ins are not offered to British players; the Commission's games warning (opens in a new tab) said they risked breaching its standards on game rules and chasing losses. Gamble features, where you can risk a win for a chance to increase it, are a different matter: they aren't banned, and whether a game includes one is decided game by game.

RTP and volatility: the two numbers to check first

RTP, or return to player, is the share of all money staked that a slot pays back over a very large number of spins. The rest, 100% minus RTP, is the house edge. UK rules require the RTP or likelihood of winning to be available before you play, under the Commission's RTS 3 standard (opens in a new tab).

The trap is that many slots exist in more than one version. The same game, same graphics, can be set to different returns:

Volatility describes how results are spread. Low-volatility games pay small wins more often; high-volatility games pay less often but can pay more when they do. Two slots with the same RTP cost the same on average, but a high-volatility one can swallow a small budget much faster before any feature lands. Bigger Bass Bonanza and Big Bamboo are high-volatility examples; Esqueleto Explosivo is a low-volatility one.

What a session of slots on mobile costs in pounds

The average cost of a spin is the stake times the house edge. At 96% RTP, the edge is 4%, so a 10p spin costs 0.4p on average, a 50p spin 2p and a £1 spin 4p. Speed matters too: at the UK minimum of 2.5 seconds per spin, the most you could play is 1,440 spins an hour. The table assumes 600 spins in an hour, an illustration rather than a measured pace.

Two lessons follow. First, a two-point drop in RTP raises the average cost of the same session by half. Second, the stake you choose matters far more than the RTP: £1 spins cost ten times as much as 10p spins on the same game.

What £20 looks like at 10p, 50p and £1

A £20 budget is 200 spins at 10p, 40 at 50p or 20 at £1 if nothing comes back. Wins get re-staked, so you'll usually play longer than that, but on a high-volatility slot, 20 spins at £1 can be over in as little as 50 seconds at the 2.5-second minimum. Lower stakes don't change the house edge; they just spread the same budget across more spins and more time. Our guide to low stakes casino games has more ideas.

How to check a slot on your phone before you spin

1. Open the game and find its info, help or paytable screen; on a phone this is often behind a small icon or menu.
2. Read the RTP figure shown there. If it's lower than the figure you've seen elsewhere, the casino is running a different version.
3. Look for the volatility rating, if the game shows one, and the maximum win.
4. Check the stake selector. In the UK it can't go above £5, or £2 if you're 18 to 24.
5. Decide your budget and stake before the first spin, and set a deposit limit in your account if you haven't.
6. Watch the net position and session time that UK games display as you play.

Our step-by-step guide to finding a game's RTP in an app shows where operators usually put this information.

UK stake limits and design rules for mobile slots

Online slots in Great Britain have stricter rules than any other casino game. The Commission's stake limit guidance (opens in a new tab) and its RTS 14 design standard (opens in a new tab) set them out.

The no-speeding rule doesn't apply to bonus or feature rounds where no extra stake is wagered, so a free spins round may move faster than the base game. Our pages on slot stake limits and why slots spin slower on UK apps explain the background.

Playing slots on a phone: screen, data and storage

• Portrait or landscape. Some slots are designed for an upright screen and others for sideways play; our page on portrait casino games covers the difference.
• Data. RNG slots generally use far less data than live casino streams, though games with heavy graphics take longer to load the first time.
• Storage. App sizes vary widely. The App Store lists the PlayOJO app at 25.4 MB, against 101.6 MB for Coral Casino and 101.2 MB for Ladbrokes Casino.
• Notifications. Promotional pushes can prompt play you didn't plan. You can turn them off in your phone's settings for each app.

Myths spread fast on social media, so to be clear: the time of day you spin, how fast you tap or how long a game has gone without a feature has no effect on the next result. Each spin is independent, and UK rules forbid games from adjusting outcomes to hit a target return.

Mobile slots reviewed on our site

These slots show the range of formats and volatility you'll meet. Figures are the published specifications; check each game's help screen for the version your app runs.

Our Gemix review shows how a cluster-pays grid plays on a phone, and you can browse every game in our mobile slot reviews.

Choosing a slots app in the UK

For slots, the questions that matter are how the app runs on your phone, how quickly it pays out and what safer-gambling tools it offers. Here's how our three slot-focused partners compare on their App Store listings:

Read our full reviews of the PlayOJO app, the Coral Casino app and the Ladbrokes Casino app, or see the wider ranking in our best slot apps list. Coral and Ladbrokes are both run by LC International Limited (Entain), so you may not be able to open new accounts at both.

Slot app welcome offers: what they're worth

All three offers are slot offers, and each pays in free spins at 10p a spin. Treat any winnings as a bonus, not an expectation, and remember the house edge still applies to every spin. 18+, terms apply.

• PlayOJO: 80 free spins on Big Bass Bonanza at 10p each for new UK customers (excluding Northern Ireland) on a first deposit of at least £10. No wagering, so winnings are paid in cash. The spins have a face value of £8; if the game runs its 96.71% version, their average return is about £7.74. It can't be combined with other offers and is only available through the designated offer link.
• Coral Casino: new players who deposit and bet £10 or more on slots get 100 free spins on selected games, worth £10 at 10p each. Accept within 48 hours, use within 7 days, and keep the winnings with no wagering. The offer runs from 1 October 2026 to 1 February 2027; Neteller, PayPal, Paysafe, Skrill, prepaid cards and certain debit cards don't qualify.
• Ladbrokes Casino: new customers who deposit and spend £10 or more on slots get 50 free spins a day for 10 days, up to 500 spins worth £50 in total at 10p each. Each day's spins must be claimed before 23:59 and used within 7 days, with no wagering. Prepaid cards, PayPal, Paysafe, Neteller, Skrill and Moneybookers deposits don't qualify.

Face value isn't the same as money in your pocket: what you keep depends on how the spins land. Our guide to free spins in casino apps explains how these offers work.

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.