Expanding wilds explained

What expanding wilds are

A normal wild symbol replaces other symbols in the single cell where it lands. The plain definition in the casinos.com slot features guide (opens in a new tab) is that a wild stands in for every symbol except scatters to help form a win. The expanding version does the same job, but first it grows to cover every row of its reel. The result is a column of wilds, so any winning route that passes through that reel now has a substitute available.

The idea is widespread. NetEnt, for example, lists expanding wilds among its signature mechanics. Many newer features are elaborate versions of the same idea, from wilds that nudge into place to reels that fill after a duel. The full list of mechanics we explain sits in our slot features hub.

How an expanding wild works on a spin

1. A wild lands somewhere on a reel, in the base game or a bonus round, depending on the game.
2. It expands to fill every position on that reel; some games only expand it when it would complete a win.
3. Every cell on the reel now substitutes for paying symbols, though usually not for scatters.
4. Wins are counted across all paylines or ways using the wild reel.
5. Unless the game says otherwise, the wild reel clears before the next spin; if it stays, it is a sticky wild.

Some games attach extras at the expansion step, most often a multiplier on wins that use the reel. Whether a wild expands every time it lands or only when it helps a win is one of the first things to check in the rules.

Expanding wilds maths on paylines and ways

On a fixed-line game, every payline passes through exactly one cell on each reel. A single wild in the middle row of reel three only helps the lines that run through that one cell. Expand it to fill reel three and every line on the game now has a wild on reel three. On a 10-line game, that is all 10 lines rather than a handful.

On a 3-row ways to win game the gain is easy to count. Ways are the number of matching positions on each reel multiplied together. A full wild reel counts as three matching positions for every symbol at once.

Every way pays the symbol's prize, so if four of a kind is worth 0.5x stake per way, three ways pay 1.5x and nine ways pay 4.5x. On taller reels the effect is bigger, because a wild reel of six rows counts as six positions. That is why expanding wilds on Megaways games, where reels can hold up to seven symbols, can swing a spin so far.

Types of expanding wild you will meet

Studios have built many twists on the basic column of wilds. These are the ones our checked data describes.

The duel version is the most unusual. Launch coverage of Bullets and Bounty (opens in a new tab) says reels expanded by DuelReels act as wilds, so the same reel both completes the win and multiplies it. The nudging version is documented in coverage of Apocalypse Riders X, which explains that an xNudge wild nudges to fill the reel (opens in a new tab) and adds one to its multiplier for each cell it moves.

Expanding wilds slots: key figures

Trillionaire Megaways pairs expanding multiplier wilds with Price Tag prizes from scatters on a Megaways layout of up to 117,649 ways. Starburst Galaxy keeps a 3 × 3 wild for its Galaxy Star feature on a grid that expands from 5 × 5 to 7 × 7. For more NetEnt titles see our NetEnt studio page.

Expanding wilds and your budget: the cost in pounds

Expanding wilds make some spins pay much more than others, but they don't change the long-run cost. That cost is set by the RTP, and the version a casino chooses matters a lot. Fist of Destruction is supplied at four settings. Here is what 300 spins cost on average at 50p a spin, which is £150 staked.

The wilds look and behave the same in every version, so the only way to know which you're playing is to open the info screen. Trillionaire Megaways at 95.68% has a 4.32% edge, so a £20 budget staked once at 50p a spin (40 spins) costs about 86p on average, though a high-volatility game will rarely land near that figure in so few spins. Our page on cost per hour turns these numbers into session costs.

Expanding wild myths

• A wild can land anywhere. Not necessarily: the paytable says which reels a wild can appear on, and some games leave out the first reel.
• Expanding wilds make a slot loose. RTP is fixed by design. If wilds expand often, the game has to balance that with smaller prizes elsewhere.
• Wilds come in hot streaks. Spins are independent; our page on whether online slots have memory explains why.
• Expanding wilds substitute for everything. Usually not for scatters, and sometimes not for bonus symbols. Check the paytable.

UK rules for slots with expanding wilds

The Commission's online slots stake limit guidance (opens in a new tab) sets a cap of £5 a spin for players aged 25 and over and £2 for those aged 18 to 24, as our stake limits page explains. Every spin must last at least 2.5 seconds, turbo and slam-stop are not allowed, autoplay has been banned on slots since 31 October 2021, and a win that returns no more than your stake can't be celebrated as a win.

Since a Gambling Commission warning in January 2020, feature buy-ins are not offered to British players, so you can't pay to jump into a bonus round packed with expanding wilds. Our feature buy rules page has the background.

How to check an expanding wild in the paytable

1. Find the wild in the paytable and see which reels it can land on.
2. Check whether it always expands or only when it completes a win.
3. Look for a multiplier and whether several wild multipliers add or multiply.
4. See whether it stays for later spins (sticky) or clears.
5. Read the RTP and pick a stake that suits your budget.

Our guide to reading casino game rules shows where these details usually sit in a help screen.

Where to play expanding wilds slots

Our partners' welcome offers are slot spins on named or selected games rather than the expanding-wild slots above, so check each casino's game lobby for those titles. 18+ and terms apply.

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Coral and Ladbrokes are run by the same company, so one person may not be able to take both. Our Ladbrokes slots guide covers its slot lobby. Slots are designed to return less than you stake over time, so set a limit before you start.

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.