How to reduce lag on your Minecraft server

Which lag is it?

• Server lag (low TPS). Everything slows for everyone: mobs freeze, blocks reappear after you break them. The server can't keep up with 20 ticks a second.
• Network lag (high ping). Only some players are affected, and things rubber-band. It's the distance or connection between them and the server.
• Client lag (low FPS). Only your game stutters. That's your computer; lower render distance or use a performance mod like Sodium.

Run tps in the console on Paper (20 is perfect), or check tick time in Jump's Overview: under 50 ms a tick means no server lag.

Find the cause

1. Install spark from Plugins & mods (it works on Paper, Fabric and Forge).
2. While it lags, run spark profiler start, wait a minute, then spark profiler stop.
3. Open the link it prints. The biggest entries show what's using the tick: a plugin, a type of entity, a farm, or chunk generation.

Fixes that usually help

• Lower `simulation-distance` in server.properties to 6 or 8. It's how far from players mobs and crops are ticked, and it's the biggest lever on CPU.
• Lower `view-distance` to 8 or 10. Players see less far, but the server loads fewer chunks.
• Pre-generate the world with Chunky (chunky radius 3000, then chunky start) while nobody's on, so exploring doesn't generate chunks live.
• Cut entities. Huge mob farms, item piles and hundreds of villagers are the classic cause. Limit them or add a kill-chamber.
• Run Paper rather than vanilla or Spigot; it's much faster with the same gameplay. Fabric servers can add Lithium and FerriteCore.
• Remove plugins spark shows taking a big share of the tick.

When it's the hardware

If the profile shows nothing unusual and TPS still drops with more players, the server needs more CPU or memory. Jump's paid plans give more memory and let CPU burst to more cores when the machine has spare, and you can change plan any time without losing the world. If one player always has high ping, move the server to the region nearer most players in Settings.

Questions