Base game meaning in slots: the base game is the ordinary spinning you pay for, outside any bonus round or feature. It is where most of your spins happen and where features are triggered, but on many modern slots a large share of the return is held back for the bonus, so the base game alone pays back less than the headline RTP.
The base game is the normal paid spinning that happens between features.
Headline RTP covers the base game and features together.
On high-volatility slots, the base game often returns well under the headline figure.
A session without a feature usually costs more than the average suggests.
Term
Base game
Also called
Main game, base spins
Opposite
Bonus game or feature
Costs a stake
Yes, every spin
Where RTP is shown
Game help screen
Base game meaning in slots, explained simply
Every slot has a resting state: the reels you see when the game loads, spinning at the stake you have set, paying line or ways wins from the paytable. That is the base game. When a trigger lands, play moves into a bonus game, such as free spins or a pick-and-win screen. When the feature ends, you return to the base game.
The term is mostly used to separate where the money comes from. Developers and reviewers talk about a game's “base game hit rate” or say “the base game is quiet” when most of the value sits in the bonus. It is one of the core entries in our slot terms glossary.
Base game versus bonus game: how they differ
Base game and bonus game compared
Base game
Bonus game
Cost
A stake on every spin
Usually no new stake; paid for by the trigger spin
Reels
Standard reel set
Often a different reel set with more wilds or high symbols
Win size
Mostly small and frequent
Fewer, often larger wins
Share of time
Most spins
A small share of spins
Extras
Sometimes random wilds or modifiers
Multipliers, sticky symbols, retriggers
Some base games have their own modifiers. Starburst, for example, has no free spins round at all; its expanding wilds and respins happen in the base game, which helps explain its low volatility rating. Many games add random wilds or similar surprises so the base game is not just waiting for a bonus. On reel sets, the switch between base and bonus strips is often where the volatility comes from.
How much of the RTP comes from the base game?
The headline RTP is the long-run return from everything combined. Developers split it between the base game and the features when they build the maths model, but most do not publish the split. The table below is illustrative only, showing how two games could both reach 96%.
Illustrative RTP splits (not real game data)
Game profile
Base game share
Feature share
Total RTP
Low-volatility base-game slot
80%
16%
96%
Balanced video slot
65%
31%
96%
High-volatility feature slot
50%
46%
96%
Progressive jackpot games show the split openly in a different way. Games Global's Mega Moolah lists an RTP of 88.12% for the base game, excluding the jackpot contribution, which is why its jackpot is so large and the regular return looks low. Our page on progressive jackpot slot machines explains that trade.
A worked base game example in pounds
Take the high-volatility profile above: 50% from the base game, 46% from features. You play 500 spins at 20p, staking £100.
Expected base game return: 50% of £100 = £50.
Expected feature return: 46% of £100 = £46, but only if features land about as often as average.
If features land on average, you get back about £96 and the session costs £4.
If no feature lands in those 500 spins, you get back roughly £50, a £50 session cost.
If one large feature lands, you could finish well ahead. That spread is what volatility means.
This is why two players on the same game can have very different evenings, and why the headline RTP is a poor guide to any single session. Our page on volatility and the guide to slot volatility and budgets build on this.
Where the base game idea came from
For most of slot history there was only the base game: three reels, a pay line, and a payout. Second-screen bonus rounds arrived with video machines in the 1990s. The Wikipedia slot machine article (opens in a new tab) credits the Australian game Three Bags Full with a second-screen bonus in 1994, and WMS's Reel 'Em In in 1996 as the first American video slot with one. Once features existed, “base game” became the useful name for everything else. Our page on the first video slot machines covers the period.
British fruit machines took a parallel route, with a main reel game feeding a separate feature trail board.
Look at the volatility rating. Low-volatility games such as Starburst lean on the base game; high-volatility ones like Book of Dead lean on features.
Check whether the base game has its own modifiers or only line wins.
Try the free demo version, after age verification, to see how often small wins appear.
Base game spins and the partner casino offers
Offer spins at both partner sites are played in the base game at a fixed 10p stake; if one triggers a feature, the feature plays out as normal. Coral gives new players aged 18+ 100 free spins on selected slots after a deposit and £10 or more bet on slots, accepted within 48 hours, used within 7 days, no wagering. Ladbrokes gives new customers aged 18+ up to 500 free spins, 50 a day across 10 days, after they deposit and play £10 on slots, each 10p, claimed before 23:59 daily, no wagering. Certain payment methods are excluded and terms apply; one operator runs both, so check the rules on holding two accounts.
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. Decide a budget before you play: plan a slot budget. Free, confidential help: National Gambling Helpline 0808 8020 133.
Frequently asked questions
What is the base game in slots?
The base game is the normal mode of a slot, where each spin costs a stake and pays from the regular paytable. It is everything outside bonus rounds and features such as free spins. Most of your time on any slot is spent there, and it is where triggers for features land. Some base games include small modifiers like random wilds. Our guide to bonus features explains what happens when you leave the base game.
Is the base game RTP lower than the advertised RTP?
Usually yes, because the advertised RTP includes the value of features as well as base game wins. If a game returns 96% overall and a third of that comes from free spins, the base game alone returns much less. Most developers do not publish the split, but progressive jackpot games sometimes show a base figure excluding the jackpot. The more a game relies on features, the bigger the gap. See what a good RTP for a slot is for context.
Why does the base game feel so quiet on some slots?
Because the game's maths reserves much of the return for bonus rounds. High-volatility slots often pay small amounts in the base game and save big wins for features, which can feel slow and costly between triggers. That is a design choice, not a sign the slot is broken or ‘cold’. Lower volatility games keep more return in the base game. Our list of high-volatility slot machines explains who those games tend to suit.
Can you win the max win in the base game?
It depends on the game. On many modern slots the top prize is only reachable during a feature, where multipliers and extra wilds stack up. On simpler games, such as classic three-reel slots, the biggest line win is in the base game itself. The help screen or paytable will show where the biggest payouts come from. Max win caps apply across the whole game cycle, whatever mode you are in. The max win entry explains how caps are quoted.
Do base game spins affect the chance of a bonus?
No, on online and most casino slots each base game spin has the same chance of triggering a feature, regardless of how many spins have passed. There is no build-up or countdown, unless the game shows a visible meter as part of its rules. Some games collect symbols across spins, and that progress is displayed on screen. Otherwise, the trigger is random every time. The page on bonus trigger odds shows how the chances are calculated.
Is a base game the same as the main game on a fruit machine?
Broadly yes. On a fruit machine the main reels are the base game, and features like the trail, cash pot or number reels are the bonus side. The difference is that many fruit machines are compensated, so what the machine offers can depend on recent payouts, unlike random online slots. Holds and nudges also happen in the main game. Our guide to how to play fruit machines shows how the two parts connect.
Gambling can be addictive. Free, confidential help is available 24 hours a day from the National Gambling Helpline on 0808 8020 133. Visit GamCare.org.uk and GamCare, or block yourself from all UK-licensed gambling sites with GAMSTOP.
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