What are idle games? They are video games where progress keeps happening with little or no input from you. You tap to earn a resource, spend it on generators that produce more automatically, then check back later to upgrade. Idle games belong to the wider incremental genre, alongside clicker games, and run on growing numbers and resets.
Researchers who studied 66 of them for a 2018 paper at the ACM CHI conference described idle games as "a recent minimalist gaming phenomenon in which the game is left running with little player interaction." This guide explains how they work, where they came from and why so many people enjoy them.
The names overlap, and many games mix all three. Wikipedia's overview of the genre draws the lines like this:
Incremental games are the umbrella term: games built on the steady, often exponential, build-up of in-game resources through repeated actions or automation.
Clicker games are incremental games that emphasize active input, such as clicking or tapping a button again and again to earn resources.
Idle games center on automation, with progress that continues while you do very little.
In a typical game you start by clicking, then buy upgrades that automate the work, so a clicker slowly turns into an idle game.
Tap to earn. You start with one simple action, usually clicking or tapping, that earns a little in-game currency.
Buy generators. You spend that currency on things that earn for you. Wikipedia notes these are often shown as buildings such as factories or farms. Each one raises your income.
Automate. Upgrades take over the tapping, so the game keeps earning without you. This is the "idle" part.
Watch costs climb. Each extra generator costs more than the last. Anthony Pecorella of the game site Kongregate explains that costs usually grow exponentially while production grows at a linear or polynomial rate, so progress eventually slows.
Hit milestones. Many games reward you for owning a set number of one generator. In Pecorella's AdVenture Capitalist example, lemonade stands get a stacking double bonus at 25 and again at 50 owned.
Earn while away. Game Developer's report on Pecorella's 2015 talk notes that in most idle games you keep progressing while you are away, even when you are completely offline. AdVenture Capitalist was one of the first to track progress while the game was not running.
Reset for a bonus. When progress stalls, you can "prestige": start over in exchange for a permanent boost.
Pecorella's numbers for AdVenture Capitalist's lemonade stand show the pattern. The price grows by 7 percent for each stand you own (a growth rate of 1.07), from a base of 4. Each stand adds the same base income of 1.67 per second. With 10 stands you earn 16.7 per second, and the next one costs about 7.87. The price keeps compounding while the income only adds up, which is why idle games eventually slow down and nudge you toward upgrades or a reset.
Prestige is the signature mechanic of the genre. Pecorella defines it as a reset of most of the game, especially generators and multipliers, in exchange for prestige currency or lasting multipliers. Wikipedia compares it to "New Game Plus" in other games, except that the bonus usually carries over to all future runs.
Why reset? According to Pecorella, each prestige lets you get farther through the cost curve before you fall behind again.
What it feels like: stages that took ages on your first run can be cleared much faster after a reset, which brings back a sense of progress.
The strategy: choosing when to reset is part of the game. Reset too early and the bonus is small. Wait too long and you waste time on slow progress.
Layers: some games stack several prestige systems. Wikipedia cites Realm Grinder, with layers called "abdicating," "reincarnating" and "ascending."
2002, Progress Quest. A self-playing parody of online role-playing games. In his GDC talks, Pecorella credits it with starting the idle genre.
Cow Clicker. Ian Bogost's satire of Facebook games, which became a popular Facebook game itself. Wikipedia calls it the first idle game to get mainstream media attention.
Candy Box! and A Dark Room. These swapped endless play for puzzle and exploration structures with endings.
2013, Cookie Clicker. Julien "Orteil" Thiennot's game made the genre popular. Pecorella called it the genre's first "major mainstream hit."
AdVenture Capitalist. A parody of capitalism and idle games, and one of the first to add monetization and offline earnings.
Mobile and Steam. Make It Rain became the first major mobile idle success, and by 2015 the gaming press noticed idle games spreading on Steam, including Clicker Heroes.
Many early idle games began as jokes. Pecorella once said it is "sorta a genre that almost doesn't want to exist; it's a joke, but despite itself, keeps being really successful."
Low pressure. Wikipedia describes the genre as a low-pressure experience with no failure states, steady progress and frequent feedback.
They fit around real life. Kotaku's Nathan Grayson, as summarized on Wikipedia, linked their popularity to low-effort distractions that slot easily into a daily routine.
Short check-ins pay off. "A quick check-in to the game allows you to advance much more quickly by shifting up the growth curve," Pecorella told the Game Developers Conference in 2015.
Planning instead of reflexes. The CHI 2018 paper discusses how idle games move players "from playing to planning."
Constant escalation. IGN's Justin Davis described a perpetual sense of escalation, where costly upgrades quickly become trivial and players feel powerful and weak at the same time.
You choose when to come back. Wikipedia compares the loop to a familiar real-world pattern: "I'm out of cash; I need to come back when I have more."
Lots of small wins. Achievements and milestones hand out frequent rewards and a sense of accomplishment.
Many idle games are free to download. According to Wikipedia, common ways they earn money include:
Premium boosts: instant currency, "time-warps" that grant hours of future income at once, permanent multipliers that survive prestige, and instant prestige.
Ads for rewards: watching an ad for a small reward, such as a burst of cash or doubled offline earnings.
A few habits keep the hobby fun. Read the App Store listing before you download, including the in-app purchase list. Decide on a spending limit, or none at all, before you start. And remember that the money in these games is just a number on a screen.
Not quite. Clicker games focus on active tapping, while idle games focus on automation. Both are types of incremental game, and many games are both.
Some do. Cookie Clicker can be played indefinitely, while Candy Box! and Universal Paperclips have endings you reach after enough progress.
Because costs and rewards grow so fast. Games show the totals with scientific notation, shorthand such as "1T" for a trillion, or special names for enormous numbers.
People debate it. Cookie Clicker's creator has described his own works as "non-games," and Pecorella has said of popular idle games that "a lot of these are just glorified spreadsheets with some really neat mechanics in it." Their popularity suggests players don't mind.
Cash Empire Clicker is an idle money tycoon game built on this same loop. You tap a money printer to earn, buy twelve income assets, hire eleven managers that automate production and use a prestige reset called IPO for permanent bonuses, and your empire keeps printing while you're offline. It's free with optional in-app purchases, and all money in the game is fictional.
Get Cash Empire Clicker free on the App Store
Read more about Cash Empire Clicker
Playing to Wait: A Taxonomy of Idle Games, CHI 2018 (NSF Public Access Repository)
Game Developer: The Math of Idle Games, Part I (Anthony Pecorella)