Minecraft guide

Minecraft Chunky Guide: Pre-Generate Your World to Stop Exploration Lag

By the ChicagoServers team · Updated November 15, 2026 · 8 min read

Generating new terrain is one of the most expensive things a Minecraft server does, which is why lag spikes often appear when players explore. Chunky pre-generates chunks in advance, so that work is done before anyone arrives. Install it, set the area with chunky radius or chunky worldborder, and run chunky start.

This guide covers installing Chunky, the commands, sizing the area, using the world border, and the Nether and End. It was checked on 2026-11-15 against Chunky's own wiki. The wiki does not list Minecraft version support, so check Chunky's project page for your version before you install. Pre-generating also uses disk space, so size the area to what players will use.

Quick answer

Chunky runs on Bukkit-based servers such as Paper, where you put it in plugins, and on Fabric, Forge, NeoForge and Sponge, where it goes in mods. Fabric also needs Fabric API.
Run chunky radius 5000, then chunky start. The wiki suggests starting at about 5000 blocks and growing later.
chunky worldborder sets the area to your world border. chunky pause and chunky continue control the task.
Pre-generate before players join, and disable map plugins while it runs, since they slow generation.
Large areas can take a very long time and a lot of disk. If the estimate is unreasonable, restart with a smaller radius.

On this page

Install Chunky
Pre-generate a world
Command reference
Use the world border
The Nether and the End
Tips for a smooth run
Chunky problems and fixes
Frequently asked questions

Install Chunky

Server type	Where Chunky goes
Bukkit-based (Paper and similar)	The `plugins` folder
Fabric	The `mods` folder, with Fabric API also installed
Forge or NeoForge	The `mods` folder
Sponge	The `mods` folder

Check your server software
Chunky does not run on a plain Vanilla server. See Paper vs Spigot vs Purpur vs Vanilla if you are unsure what you are running.
Download the right build
Download Chunky for your platform and Minecraft version from the project's official download pages, and check that it supports your version.
Upload it
On the Files tab, upload the .jar to plugins (or mods for a mod server).
Restart
Click Restart. When the server is back, type chunky on the Console tab to confirm it loaded.

Plugin installs in general are covered in how to install plugins on a Paper server, and mods in installing Forge and Fabric mods.

Pre-generate a world

Run these on the Console tab, with or without the slash. If you run them as a player, you need the permission to use Chunky.

Choose the world
Pick which world you are generating. Without a name it uses your current world.
```
chunky world world
```
Set the center
Use the spawn point, or give coordinates.
```
chunky spawn
```
Set the radius
The radius is in blocks. The wiki suggests starting around 5000 and growing later. Suffixes work: k for thousands of blocks and c for chunks.
```
chunky radius 5000
```
Start
Chunky shows progress, including chunks done, percent, estimated time and speed.
```
chunky start
```

Command reference

Command	What it does
`chunky start`	Starts pre-generation using your selection, or values given in the command.
`chunky pause [world]`	Pauses tasks and saves progress.
`chunky continue [world]`	Resumes current or saved tasks.
`chunky cancel [world]`	Stops and deletes tasks. They cannot be resumed. Chunks already generated are not deleted.
`chunky progress`	Shows progress for all tasks.
`chunky world [world]`	Sets the target world.
`chunky shape SHAPE`	Sets the shape, for example `square` or `circle`.
`chunky center [x z]`	Sets the center. Without coordinates it uses your location.
`chunky radius R [R2]`	Sets the radius. A second value applies to rectangles and ellipses.
`chunky spawn`	Sets the center to the world's spawn point.
`chunky worldborder [world]`	Matches the center and radius to the world border.
`chunky corners x1 z1 x2 z2`	Sets the area from two corners.
`chunky silent`	Toggles update messages.
`chunky quiet SECONDS`	Seconds between update messages. 0 prints one for every chunk.

Use the world border

A world border stops players wandering beyond the area you pre-generated. Chunky can read it for you. Vanilla's worldborder set takes the full width, so a width of 10000 is a radius of 5000.

Set the border
Centre it, then set the width.
```
worldborder center 0 0
worldborder set 10000
```
Match Chunky to it
Chunky copies the border's center and radius. Using a world argument needs a recent Chunky version.
```
chunky worldborder
```
Start
Run the task.
```
chunky start
```

The Nether and the End

Change only the world, keep the radius, and start again. World names vary by server. Chunky's wiki lists common ones: world or overworld, world_nether or the_nether, and world_the_end or the_end. Use chunky world with the name your server uses, which you can see in the Files tab. Our backup guide explains where dimensions are stored on different versions.

Example for a Nether run

chunky world world_nether
chunky start

Tips for a smooth run

Run it before players join. Generating while people play can add lag. See the lag guide.
Start small. Grow the radius later instead of committing to a huge area.
Disable map plugins while it runs. The wiki says this usually makes generation faster.
Watch disk space. Big worlds use a lot of storage and make backups larger.
Back up before trimming. chunky trim deletes chunks outside the selection by default, cannot be undone without a backup, and needs a restart afterwards.
Changing the seed after generating causes seams. See the seed guide.

Chunky problems and fixes

What you see	Likely cause
Unknown command	Chunky is not installed or did not load. Check the file is in `plugins` or `mods` and read the Console tab.
You do not have permission	Run it from the console, or give the player the permission.
It finished far too quickly	The default radius of 500 was used. Set `chunky radius` first.
The estimate is huge	The radius is too big. Cancel and use a smaller one.
Slow generation	A map plugin is installed, or the CPU or disk is slow.
Wrong dimension generated	Run `chunky world` with the name you want first.
Progress lost after a stop	Use `chunky pause`, which saves progress, then `chunky continue`.

Looking for a host? See Minecraft server hosting.

Frequently asked questions

What does Chunky do on a Minecraft server?

It pre-generates chunks in advance so the server does not have to generate terrain while players explore, which avoids lag spikes.

How do I pre-generate a Minecraft world with Chunky?

Set the world and center, set a radius with chunky radius, for example 5000, then run chunky start. Use chunky progress to watch it.

How big should I pre-generate my Minecraft world?

Chunky's wiki suggests starting around a 5000 block radius and growing it later. Larger areas take a long time and a lot of disk space.

How do I pre-generate to the world border?

Set the world border, then run chunky worldborder to copy its center and radius, and chunky start.

Can I pause Chunky?

Yes. chunky pause saves progress and chunky continue resumes it. chunky cancel stops and deletes the task.

Does Chunky work on Vanilla servers?

No. It runs on Bukkit-based servers such as Paper, and on Fabric, Forge, NeoForge and Sponge.