Tick
One step of the Minecraft game loop. The server runs 20 ticks per second, so one tick lasts 50 milliseconds.
A tick is the basic unit of time in Minecraft. The server does not simulate the world continuously; it updates it in steps. In each game tick it moves entities, runs AI, updates redstone, grows plants, processes player input and sends the changes to clients. At normal speed there are 20 ticks per second, so one tick is 50 milliseconds.
Kinds of ticks
- Game tick: the main step described above. All in-game timings, such as smelting time or potion duration, are measured in game ticks.
- Redstone tick: the delay unit used for repeaters and many redstone components. One redstone tick equals two game ticks.
- Random tick: in each game tick, a few random blocks in every section of each ticked chunk receive an update. This is what makes crops grow, leaves decay and ice melt. The number per section is set by the
randomTickSpeedgame rule, which defaults to 3.
Recent versions also include a /tick command for operators to freeze, step or change the tick rate, mainly useful for testing redstone and farms.
Why it matters for server owners
Everything that makes a server lag comes down to the server not finishing its ticks in time. MSPT measures how long each tick takes, and TPS shows how many ticks actually happen per second. Only chunks within the simulation distance of a player, plus chunks kept loaded by the game, are ticked at all.
Practical tip
Do not raise randomTickSpeed on a multiplayer server to speed up farms. It multiplies work in every ticked chunk, and the extra load grows with player count.