An expanding wild is a wild symbol that grows to fill every position on its reel once it lands, turning one substitute into a column of them. That single change can complete several paylines at once, and in many slots, Starburst being the best-known, the expanded reel then holds in place while the others respin.
Once it lands, this kind of wild stretches from one position to cover its entire reel.
Because a full reel crosses many paylines, one expansion can complete several wins in a single spin.
Expanding wilds often lock and trigger a respin, but each game sets its own rules.
An expanding symbol, as in Book of Dead, is a different mechanic and isn’t necessarily wild.
Type
Wild symbol variant
What it does
Fills its whole reel after landing
Often paired with
A respin with the wild held
Best-known example
Starburst
Where to check
Game rules in the slot’s menu
How an expanding wild works
A standard wild symbol helps on the one position it occupies. The expanding version goes further: as soon as it lands, an animation stretches it up and down until the whole reel is wild. On a 5×3 grid that turns one wild into three; on a taller grid it may become five or six.
That matters because of how paylines run across the screen. A fully wild reel sits on every line that passes through that column, so it can complete wins on several lines at once. On ways to win slots the effect is similar: every symbol on the neighbouring reels can connect through the wild column.
Many games restrict expanding wilds to certain reels, most often the middle ones, because a wild on the first reel would let almost any combination start. The game rules say which reels can carry them.
Expanding wilds in Starburst and other slots
In Starburst, the NetEnt classic, wilds can appear on reels 2, 3 and 4. When one lands it expands to fill the reel, locks, and the other reels respin. If another wild lands during that respin it expands too and earns a further respin, up to three in total. Starburst’s lines pay both left to right and right to left, which makes a wild middle column especially useful.
Slot
Mechanic
When it happens
Starburst
Wild expands on reels 2–4, locks and triggers a respin
Base game
Starburst XXXtreme
Expanding wilds that can carry multipliers
Base game and features
Thunderstruck II
Wildstorm can turn whole reels wild at random
Base game
Book of Dead
A chosen symbol expands (not a wild)
Free spins round
The last row is a common source of confusion. In Book of Dead, a special symbol is picked before the free spins round you trigger with three or more scatters, and it expands across its reel when enough of it lands to pay. It pays on any position rather than along lines, but it doesn’t substitute for other symbols, so it isn’t a wild. You can compare it with Starburst XXXtreme and Thunderstruck II on their own pages.
An expanding wild example with numbers
Take an imaginary 10-line slot on a 5×3 grid at £1 a spin, so each line carries 10p. Reels 1 and 2 show a blue gem on both the top and middle rows. A wild lands at the top of reel 3.
As a normal wild, it completes one line: three blue gems on the top row. If three gems pay 4x the line bet, that is 40p.
Expanded to cover the reel, it also completes the middle row and any diagonal lines that pass through matching gems. Two lines at 40p each pay 80p.
If the slot then respins the other reels with the wild held, a further gem on reel 4 could lengthen those lines to four of a kind.
Notice that 80p on a £1 spin is still a loss of 20p. UK-licensed slots aren’t allowed to celebrate a return equal to or below your stake with fanfare, so an expansion like that should play out quietly, and the net position on screen will show the true result.
What expanding wilds look like on a phone
On a small screen in portrait, the expansion is usually the most visible event in the game: the column lights up and the other reels may dim while they respin. Respins inside a feature run on their own without you tapping again. That is part of the game design, not autoplay, which UK rules ban.
If you want to understand exactly which reels can expand and whether a respin follows, open the slot’s menu and choose the rules or paytable. Rotating to landscape on most games gives the reels more room and makes it easier to follow which lines a wild has completed. Our guide to portrait versus landscape slots covers the trade-offs.
Animations for expansions and respins use a little more battery than plain spins. If your phone is low, a power-saving mode can make slots feel slower but won’t change any result.
Why expanding wilds matter for how a slot feels
Slots built around expanding wilds in the base game tend to produce regular small and medium wins rather than rare large ones, which is why Starburst is listed as low volatility. Games that save expansions for a bonus round push their value into less frequent features.
Either way, the frequency of expansions is already part of the published RTP. They make results feel livelier but don’t shift the long-run maths away from the casino’s edge, so treat them as part of the entertainment you are paying for.
Related terms
Sticky wild: a wild that stays put for several spins rather than spreading.
Respin: the follow-up spin that often comes with an expansion.
Multiplier: some expanding wilds also multiply the wins they join.
Hit frequency: how often any win lands, which expanding wilds tend to raise.
Where to play expanding wild slots in an app
Coral gives new players aged 18+ 100 spins at 10p on selected slots after they deposit and stake £10 on slots, and Ladbrokes gives up to 500 spins at 10p, released as 50 a day for 10 days, on the same kind of qualifying £10 slot stake. Spin winnings from both carry no wagering. The games the spins apply to are set by each offer, and full terms apply.
Both apps carry large libraries of classic and modern slots, and their welcome spins carry no wagering on winnings. 18+, deposit and £10 slot stake required, terms apply.
Coral and Ladbrokes are both run by LC International Limited (Entain). If you already hold an account with one Entain brand, you may not be able to open a new account with another; check the terms before signing up.
Significant terms: 18+. New players only. Offer runs 01/10/2026 to 01/02/2027. Deposit (certain types excluded) and bet £10+ on slot games to get 100 free spins (selected games, £0.10 each, 48 hrs to accept, valid 7 days). No wagering on free spin winnings. Deposits by Neteller, PayPal, Paysafe, Skrill, prepaid cards and certain debit cards do not qualify. Restrictions and T&Cs apply. GamCare.org.uk
Read the Coral reviewLicence: LC International Limited, UKGC account 54743. Offer checked 5 October 2026.
Significant terms: 18+. New customers only, from 14/11/25 until further notice. Certain deposit methods excluded. Deposit and spend £10+ on slots for 50 free spins a day during the first 10 days after first deposit and registration (max 500, £0.10 each, selected games, claim before 23:59 each day, valid 7 days). No wagering. Prepaid cards, PayPal, Paysafe, Neteller, Skrill and Moneybookers deposits do not qualify. Restrictions and T&Cs apply. GamCare.org.uk
Read the Ladbrokes reviewLicence: LC International Limited, UKGC account 54743. Offer checked 5 October 2026.
18+. Gambling should be entertainment that costs money, not a way to make it. Set a deposit limit before you play: how to set limits. Free, confidential help: National Gambling Helpline 0808 8020 133.
Frequently asked questions
What is an expanding wild in slots?
An expanding wild is a wild symbol that grows to cover its entire reel after landing. On a three-row slot one wild becomes three, so it can complete wins on several paylines in the same spin. Many slots also hold the expanded reel in place and respin the others. Each game sets which reels can carry expanding wilds and what follows, so check the rules screen in the slot. The wild symbol entry covers wilds in general.
How does the Starburst expanding wild work?
In Starburst, wilds can land on reels 2, 3 and 4. A wild expands to fill its reel, stays in place, and the remaining reels spin again. If a new wild appears during that respin, it expands too and earns another respin, up to a maximum of three. Wins pay both left to right and right to left. The Starburst page explains the rest of the game, including its published RTP and low volatility.
Is an expanding symbol the same as an expanding wild?
No. An expanding symbol, like the special symbol picked at the start of the Book of Dead free spins round, spreads across its reel when enough of it lands to pay, but it doesn’t substitute for anything. A wild that expands does substitute, helping other symbols complete wins. Both can turn a reel into a single column, which is why they get mixed up. See the Book of Dead page for how its expanding symbol behaves.
Do expanding wilds make a slot pay more?
They change how wins arrive, not how much the game returns over time. The frequency and power of expanding wilds are built into the published RTP, so a slot full of them can return the same or less than a plainer game. They often make results more frequent and less spiky, which suits players who prefer longer sessions on a fixed budget. The volatility entry explains the trade-off between frequent small wins and rare large ones.
Why don’t I have to tap spin during an expanding wild respin?
Because the respin belongs to the feature that the wild triggered. The game runs it automatically as part of the same paid spin, much as a free spins round plays out on its own once triggered. That isn’t autoplay, which UK rules have banned on slots since October 2021. You still decide when to start each paid spin. Our page on UK slot design rules on mobile lists the related requirements.
Can an expanding wild land on the first reel?
It depends on the game, but many slots keep expanding wilds off the first and last reels. A fully wild first reel would let a huge range of combinations start, so developers usually restrict them to the middle columns. Starburst, for instance, allows them only on reels 2 to 4. The slot’s paytable will show which reels the wild can appear on. Our guide to reading a paytable on mobile shows where to look.
Gambling can be addictive. Free, confidential help is available 24 hours a day from the National Gambling Helpline on 0808 8020 133. Get support from GamCare or NHS gambling support, or block yourself from all UK-licensed gambling sites with GAMSTOP.
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