Pre-generate a Minecraft world with Chunky

Minecraft generates new chunks as players wander into unexplored areas. Chunky builds a set area ahead of time, so players only load chunks that already exist. This guide installs Chunky on a Paper or Purpur server, runs a pre-generation from the console, and covers the settings that stop it stalling.

Checked against Chunky 1.5.3 on Paper 26.3, October 2026.

Install Chunky

1. Open Plugins under Content in the left rail.
2. Leave the Modrinth source chip selected, search for Chunky and click Install.
3. Open the Console tab and click Restart. Plugins load only at startup.

The Paper build has no dependencies. Fabric, Forge and NeoForge servers can run Chunky as a mod from the Mods tab. On Fabric it needs Fabric API, which the install prompt offers.

Choose what to generate

Chunky reads its target from a selection: a world, a shape, a centre and a radius. Type these into the Send a command box in the Console tab, without the leading slash.

chunky world world
chunky shape square
chunky center 0 0
chunky radius 2000

The radius is in blocks. 10k means 10000 blocks, and 625c means 625 chunks. Check the result with chunky selection. If you never set anything, Chunky uses a square in the overworld centred on 0, 0 with a radius of 500.

You can also give everything in one line: chunky start world square 0 0 2000.

If your world has a border, chunky worldborder copies its centre and radius into the selection. Remember a border's size is a diameter, so the radius is half of what /worldborder set was given.

Start, pause and finish

1. Take a backup first from the Backups tab, so a mistake costs you nothing.
2. Run chunky start. Progress prints in the Console, and chunky progress shows it on demand.
3. To stop for a while, run chunky pause. Run chunky continue to pick it up again.
4. To abandon the task, run chunky cancel. Chunks already generated are kept.

By default a task does not resume after a restart. Chunky saves running tasks when you run chunky pause and when the server shuts down normally, and the continue-on-restart option in its config makes it carry on by itself. The file is config.yml in the plugins/Chunky folder. Edit it in the File Manager and click Save.

Chunky skips chunks that already exist, so it is safe to run on a world players have already explored.

Stop the server pausing while it works

A Minecraft server pauses itself a set time after the last player leaves. Chunky's FAQ says to keep the game unpaused during a run, which for a multiplayer server means setting pause-when-empty-seconds to -1. The Config Editor does not list that key, so edit the file directly.

1. In the File Manager, open server.properties and set pause-when-empty-seconds=-1.
2. Click Save and restart the server.
3. When the run finishes, set it back. The default is 60, as described in Minecraft server.properties explained.

Avoid /tick freeze during a run for the same reason.

Watch disk and memory

World size does not grow in a straight line. Each small increase in radius adds a much larger area, so start with a modest radius and raise it once you can see how much space it took. The Disk Usage card on the Console tab and the Disk Analyser show what the world now uses.

Chunky's FAQ recommends at least 4 GB of RAM while generating, and notes that high RAM use during a run is normal because the server loads and unloads chunks rapidly. RAM comes with your plan, and Change plan in Settings is how you raise it (see Upgrade or downgrade your plan).

If something goes wrong

• Lag, crashes or stalls during a run. Test with only Chunky installed. Chunky's FAQ names Dynmap rendering as a known cause, so run dynmap pause all first if you use it, and dynmap pause none when you finish. See Set up Dynmap on your Minecraft server.
• You generated too much. chunky trim deletes chunks outside a selection, for example chunky trim world square 0 0 10k. Trim asks you to confirm before it deletes anything, so read that confirmation message carefully before you commit. Deleted chunks cannot come back without a backup, and the server must be restarted afterwards. Chunky cannot delete chunks the server currently has loaded.
• Not sure where the time goes. Profile with spark, as described in Reduce Minecraft lag with spark and plugins.