An idle game gives you something that earns on its own, then asks you to decide how to spend what it makes. Every purchase raises your income, but each one costs more than the last, so you’re always weighing the next move. Upgrades multiply your output, the game counts the time you were away when you come back, and eventually you reset for a permanent bonus that makes the next run faster.
That’s the whole genre in a paragraph. The rest of this article explains why each piece is there, with real numbers from Bunny Bakery, a cozy idle game whose rules are simple enough to show the math.
The core loop in five steps #
- Earn by hand. You tap something (a cookie, a lemonade stand, a chef bunny) to earn your first currency.
- Buy producers. You spend it on things that earn automatically: buildings, businesses, stations, managers.
- Watch costs climb. Each producer costs more than the one before, usually by a fixed percentage.
- Multiply with upgrades. One-time purchases double or triple what your producers make.
- Reset for a permanent bonus. When growth slows, you give up your progress for a multiplier that carries into the next run.
Cookie Clicker, which started as a free browser game in 2013, made this loop famous, and most idle games since then are variations on it. AdVenture Capitalist swaps cookies for businesses and uses managers to automate them. Egg, Inc. dresses the same loop up as a 3D egg farm. The details change; the skeleton doesn’t.
Why do costs go up by a percentage? #
If every producer cost the same, you’d just buy the best one forever and the game would have no decisions in it. Instead, each purchase costs a fixed percentage more than the last. Bunny Bakery uses 15%, so the price of your next station is the base price times 1.15 for every one you already own.
Here’s what that does to the price of a Cookie Counter, which starts at 100 coins:
| Which one you’re buying | Price |
|---|---|
| 1st | 100 |
| 10th | about 350 |
| 25th | about 2,900 |
| 50th | about 94,000 |
| 100th | about 102 million |
Each Cookie Counter still makes the same 1 coin a second, but the 100th costs a million times more than the first. That’s the engine of the whole genre. Costs grow exponentially while each producer’s output grows only in a straight line, so stacking one producer forever stops making sense. You’re pushed to buy the next, more expensive type of producer, and to look for upgrades that change the math.
Why do the numbers get so big? #
Because multipliers stack by multiplying, not adding. In Bunny Bakery, each station has five upgrades that each double its output, so a station with all five makes 32 times its base rate. Four global upgrades add +25%, +25%, +50% and +100%, which multiply out to about 4.7 times. Permanent bonuses from achievements and prestige multiply on top of that.
Put a few of those together and a bakery that made 10 coins a second an hour ago makes millions. Idle games lean into this: they abbreviate numbers as K, M, B and T, and part of the fun is watching the suffixes change.
How does offline progress work? #
Idle games don’t actually run while they’re closed. When you reopen one, it looks at how much time has passed and pays you for it based on your production when you left, usually with two limits:
- A reduced rate. Bunny Bakery pays 50% of your normal income for time away.
- A cap. Bunny Bakery stops counting after 8 hours.
The cap and reduced rate exist for a reason. They reward coming back without making it optimal to stay away forever. A player who checks in twice a day earns more than one who checks in once, but a player who forgets for a week doesn’t fall hopelessly behind either. We walk through the exact math in how Bunny Bakery offline earnings work.
What does prestige do? #
Eventually every idle run slows down. The next producer is so expensive that you’d wait hours for it. Prestige solves that. You reset your producers and upgrades to zero, and in exchange you get a permanent currency that multiplies everything in future runs.
The trick is that early game is fast. With a permanent bonus, you race back through the cheap early purchases and reach the slow part further along than before. Each reset pushes the wall back a little.
Games handle this differently. Bunny Bakery gives Sparkle Stars on a square-root curve (1 billion coins earns 1 star, 4 billion earns 2, 100 billion earns 10), each worth +2% production. AdVenture Capitalist has Angel Investors. Egg, Inc. describes a “nested” prestige system, and Antimatter Dimensions stacks several layers on top of each other. We compare them in what prestige means in idle games.
What’s the point of tapping? #
Tapping matters most at the very start, before you have producers, and it’s what makes an idle game feel like a game rather than a spreadsheet. Most idle games also reward attention in small ways:
- Surprise bonuses. Cookie Clicker has golden cookies. Bunny Bakery has a golden bunny that hops across the screen every 3 to 6 minutes and pays about three minutes of production if you tap it.
- Temporary boosts. Many free idle games offer 2x or 3x income for a few minutes, often in exchange for watching an optional ad.
- Daily rewards. Coming back on consecutive days builds a streak.
None of these are required. The idle part keeps working either way, which is why the genre suits people who want a game they can check on rather than sit with.
How do idle games make money? #
Most are free. They pay for themselves in a few common ways:
- Rewarded ads, where you choose to watch an ad for a boost or bonus.
- Full-screen ads at natural breaks, like after a reset.
- In-app purchases for premium currency, time skips or ad removal.
- A one-time price, for games like Universal Paperclips ($1.99, no ads, no in-app purchases).
Bunny Bakery, for example, is free with ads and has no in-app purchases at all. If you want to know which model suits you, idle vs clicker vs incremental games sorts the genre by play style, and why idle games are so satisfying looks at why the loop is so hard to put down.
Frequently asked questions #
Do idle games keep running when the app is closed? #
No. They calculate what you would have earned from the time that passed when you reopen them, usually at a reduced rate and with a cap. That’s why many idle games show a “while you were away” screen on launch.
Why do idle games have prestige? #
Because exponential costs eventually make progress crawl. Prestige resets you to the fast early game with a permanent bonus, so each run gets further than the last.
Are idle games pay to win? #
Most idle games are single-player, so purchases mostly buy time rather than an edge over other people. Where games have shared events, like Egg, Inc.’s co-op Contracts, spending can matter more.
What is the difference between an idle game and a clicker game? #
A clicker game centers on tapping to earn, while an idle game centers on progress that continues without you. Most modern games mix both: you tap at the start and let automation take over.