TPS (ticks per second)
Ticks per second: how many game updates the server completes each second. The target and maximum is 20.
TPS stands for ticks per second. A Minecraft server runs its world in fixed steps called ticks, and it aims for exactly 20 of them per second. TPS tells you whether it manages that.
What low TPS looks like
At 20 TPS the game runs at normal speed. When the server cannot finish a tick in time, TPS drops and the whole world slows down: crops grow slower, mobs move in bursts, redstone clocks stretch, and players see blocks reappear after breaking them or get pulled back after moving. This is server lag, and it affects everyone at once. It is different from high ping, which is a network delay for one player.
Checking TPS
- On Paper and its forks,
/tpsshows averages over the last 1, 5 and 15 minutes. - Vanilla has no
/tpscommand, but a profiler such as spark shows it.
TPS cannot go above 20, so a reading of 20 tells you nothing about how close you are to the limit. For that, look at MSPT: a server at 20 TPS with 45 ms per tick is about to start lagging, one at 15 ms has plenty of headroom.
Common causes of low TPS
- Too many entities in one place, such as large mob farms or item piles.
- Heavy redstone or hoppers running in loaded chunks.
- Generating new terrain while players explore.
- A high simulation distance with many players spread out.
- Plugins or mods doing expensive work on the main thread.
- Too little CPU speed per core, see single-thread performance.
Practical tip
Do not guess. Run a profiler during the lag, find the one thing that uses most of the tick, and fix that. The guide on how much RAM a server needs also explains why adding memory alone rarely raises TPS.