Agar.io runs on the developer's own site
This game is hosted and operated by its own developer, so we send you straight to the official version rather than embedding a copy. You get the current build, from a source we do not have to vouch for second-hand.
Play Agar.io on the official site →Opens in a new tab. The destination site is not under our control.
Agar.io
Agar.io is the game that started the .io genre. You are a cell in a petri dish full of other players' cells, and the only rule is that bigger eats smaller.
| Category | IO Games |
|---|---|
| Players | Massively multiplayer |
| Developer | Matheus Valadares |
| Released | 2015 |
| Controls | Mouse + keyboard |
| Difficulty | Medium |
| Typical session | 3 – 20 min |
| Price | Free |
How to play Agar.io
These are the controls for the browser version. Click into the game area once before you start so the game has keyboard focus.
Agar.io tips and strategy
- Do not split unless you are certain the target cannot eat the piece you launched.
- Stay near the edge of the map while small. Corners limit the angles a bigger cell can attack from.
- Feed viruses to hide, but remember they split you if you touch them while large.
- When you are the biggest cell on the server, split-teaming is your main risk. Watch for two mid-sized cells cooperating.
- Ejecting mass to speed up a smaller cell is a legitimate way to bait a big player into a virus trap.
About Agar.io
Your cell follows your mouse. Run over smaller cells and floating food to absorb them and grow. Touch a larger cell and you are instantly eaten. That single rule generates a surprising amount of strategy.
The interesting mechanic is splitting. Press space and your cell divides, launching half of your mass forwards. It is how you catch prey that is trying to escape, and also how careless players lose everything to a bigger cell waiting nearby.
There is a third action — ejecting mass with W — which is used to feed teammates or to bait opponents into a trap. Combined with splitting, it gives the game a genuine tactical layer under the simple surface.
Agar.io: frequently asked questions
Is Agar.io free to play?
Yes, Agar.io is free to play in the browser. It has cosmetic skins which are optional and not required to play well.
What do the keys do in Agar.io?
The mouse steers your cell, space splits it in two and W ejects a small amount of mass.
Why do I keep dying instantly in Agar.io?
Almost always from splitting near a cell you misjudged as smaller, or from sitting in open space where a large player can drive straight over you.
Can you play Agar.io with friends?
Yes. There are team modes, and in them the W key is mainly used to feed mass to a teammate rather than as a solo tactic.